AALTO UNIVERSITY

Delta Robot Kon-41.3131 Mechatronic Exercises; Final Report

Mäntylä Jesse, Vauhkonen Niclas, Orhanen Samppa

29.4.2014

Table of Contents

1 Introduction ...................................................................................................................................... 2

2 Technologies ..................................................................................................................................... 4

2.1 Mechanical design ...................................................................................................................... 4

2.2 Electronic design ........................................................................................................................ 4

2.3 Control system design ................................................................................................................ 5

3 Target of the project ......................................................................................................................... 6

3.1 Primary target............................................................................................................................. 6

3.2 Secondary targets ....................................................................................................................... 6

4 Project plan ....................................................................................................................................... 7

4.1 CAD-model .................................................................................................................................. 8

4.2 Bill of Materials ......................................................................................................................... 10

4.3 Preliminary budget ................................................................................................................... 11

4.4 Actual budget based on purchases .......................................................................................... 12

5 Kinematics ....................................................................................................................................... 14

5.1 Code for the robot .................................................................................................................... 21

6 Physical structure ............................................................................................................................ 23

7 Summary ......................................................................................................................................... 25

Sources ............................................................................................................................................... 26

1 Introduction

Delta robots are widely used in automated processes as pickers. For example delta robots can be

used to pick and package products from production line. Usually delta robots are implemented in

vertically positioned portals, like in Figure 1, but the idea can be implemented also in horizontally

positioned portals. At its simplest delta robot consists of a frame portal, three actuator arms and

three motors. The motors can be servomotors like in Figure 1 but also other type of motors can be

used. One example of a different kind of actuators motor solution is depicted in Figure 2.

Figure 1. A traditional delta robot, with three servomotor controlled actuator arms and a tripod-like

frame.

Figure 2. Another solution for the actuator motors.

Delta robots are also quite commonly build as an exercise for control mechanics and the internet

is full of different reports and guides on how to build your own delta robot. However, most of the

homemade delta robots are quite rough. The main difficulty with the traditional servomotor

controlled delta robot seems to be the kinematics of the actuator arms and the control system

needed to operate the fluently.

This report is a journal our team wrote during our own process of designing and building a

functional delta robot. The driving force for the project was the course Mechatronics Exercises and

the project is conducted within the restrictions of the course. The report has been written during

the process, so that the reader can follow our team’s designing and learning process as closely as

possible. We haven’t deleted the parts where we have gone wrong and instead we let the report

show exactly what we did and how we managed to overcome the problems we had during the

project.

2 Technologies

The basic construction of a working delta robot is rather straight forward. It basically requires

three motors and a control system to drive the motors in a sensible way. In our case the control

system is based on an Arduino Uno board. To make the robot functional we will also need a

mechanically working frame, but this should be rather simple to achieve as the proportions of the

arms aren’t strictly restricted. Below we have explained in greater detail the required skills and

components and the set targets for our project.

2.1 Mechanical design

The mechanical design of the robot must be simple yet effective. Also the parts used for the frame

and the moving actuator arms needs to be quite cheap. The proportions of the actuator arms are

not that crucial as the control system can take the slight proportion errors into account if it is

programmed correctly. However, to make the robot as effective as possible, the actuator arm

proportions should be designed so that all three of them are identical and that the control system

code can be written in a simple way. This is just to decrease the workload on the programming

part of our project as all three members of our group are from a mechanical engineering

background. By default the mechanical system design should be our team’s strongest aspect.

Component wise we are planning on doing the actuator arms so that they can be adjusted to get

the robot to work as effective as possible. We planned to make our robot look light weight but be

sturdy and rigid enough for the actuator to be accurate. The actual way to achieve our goals will

be achieved through using lightweight aluminum sheets and parts, whose structural strength will

be achieved through effective structural design.

2.2 Electronic design

The electronic design is a rather simple and straight forward step. We are using an Arduino Uno

board as our control board and RC-servomotors as motors. We are going to keep the electronic

design as light as possible, so we can focus more on the programming part of the project. The

power supply for our RC-servomotors is an old smart phone charger, and the Arduino board will

be powered through a PC.

2.3 Control system design

The control system is going to be the hardest part of the project for our team as all of us are

coming from a mechanical engineering background. However we have some knowledge about

basic programming but, at this point, the level of programming needed to make the robot work is

still unclear to us. We use the tutorials found in the internet to give us guidelines to design the

control system for our robot.

3 Target of the project

3.1 Primary target

The minimum target of our delta robot project is to make robot that can move rationally on the

area that the construction limits. Delta robot should be able to in a cylinder with about 30 cm

diameter and 30 cm height. The movement should be accurate enough to demonstrate

capabilities of delta robots. If our team achieves this goal it can be said that we succeeded to

design and build a delta robot.

There is a lot of information and tutorials how to make delta robot, which makes it easier to

achieve the target. However, making delta robot requires knowledge from mechatronics and at

the beginning of the course, our groups experience level is not high enough to make a higher level

target as our primary target. The actual implementation of the functional delta robot does not

require a lot of time, but the learning the essential information can increase the workload a lot.

3.2 Secondary targets

Our group has considered several possible additional features to the delta robot. We are going to

make the moving parts of delta robot light, so that the movement of the robot would be fast and

accurate. We are also trying to make the robot look as it is not a “Do it yourself” –delta robot, but

rather a thought out design.

The other considered features are related to the functionality. The delta robot could have

functionality to draw a picture, move based on input of the keyboard or joystick, identify and pick

up things or maybe some closed loop solution. We didn’t want to decide our actual function at this

point of the project as we wanted to make a versatile and adjustable robot.

4 Project plan

Our main idea behind the project plan was to concentrate on our strongest fields and get them

completed as soon as possible and then maximize the time to solve the problems related to our

teams weaker fields (electronics and control design). The first step to get our project started was

to create a CAD model and a project timeline. We planned our project timeline to help us reach

the goals and ideals we set for out project. The timeline is attached below. We will use RC-servo

motors as the actuators, as they are relatively cheap and easy to control.

Mechanism is finished Moving robot

Functional robot

Finished product

16.2. 1.3.

16.3.

1.4. 16.4.

23.4.

CAD Assembly/manufactory

Designing and making the function

Selecting main components Electronics and program Testing and tuning

Documentation

4.1 CAD-model

In Figure 3 is depicted our own CAD design for the robot project. The idea behind the CAD model

was to get a better knowledge of how the kinematics of delta robots work and produce an

accurate enough BOM (Bill of Materials) to base our budget on and to start gathering parts

needed for the project. The yellow parts are threaded, red parts are store bought and white parts

are custom made. We wanted to make our design adjustable so we could fix possible design flaws

in the prototyping phase. The adjustability will come through the threaded lower actuator arms

and adjustable ball end mounting method. The electronic components will be installed above the

top plate on a suitable stand.

The frame was built from sheet metal to make the manufacturing and prototyping easy and cheap

and give our delta robot unique and futuristic look. Frame legs get their needed rigidity from the

structural design. The frame leg design is done so, that the robot can be flipped upside down, and

still remain functional without compromising the electronic installation above the top plate.

Figure 3. Our own design of a delta robot ready to be studied with simple CREO based mechanism

simulations.

Even though the simulations we ran with our CAD model are very simple, we gained a better

understanding of delta robot kinematics. For example we found out that the upper actuator arm is

far more remarkable in terms of robot reach than the lower actuator arm. However by extending

the lower arm we can limit the angular rotation of the ball joints. The model also indicated that

the structure is somewhat self-balancing in terms of the actuator end staying parallel to the top

plate. We were also able to verify that the design we build is able to meet the requirements we set

in our project start report. The BOM for the robot is explained in the next chapter.

4.2 Bill of Materials

In Figure 4 is depicted our current BOM (Bill of Materials) based on our CAD-model. The BOM does

not include any control electronics to keep it simple enough for our project purposes. The

mechanical BOM does also help us through our project timeline to start building our delta robot

mechanics. The nut and bolt quantities in the BOM might not be correct.

Figure 4. Bill of Materials.

4.3 Preliminary budget

To begin the construction as soon as possible we needed to know the rough costs of the store

bought parts of the robot. Store bought parts include RC servo motors, servo arms and ball joints.

Also the lower actuator arms will be built from store bought materials. The prices of RC servos

suitable for our project range from 20€ a piece to 70€ a piece. The more expensive the servos are,

the faster, more accurate and stronger our robot will become. The servo arms come with the

servos or if we decide to upgrade to aluminum arms, they will be around 7€ to 10€ a piece. The

easiest and most accurate approach to ball joints would be to use RC-car ball studs and –cups.

These cost around 14€ for 6 ball cups and 12€ for 4 ball studs. This would mean the store bought

parts for our project would cost between 120€ to 300€. The prices are from Finnish retailer’s web

shop and they are all usually “in stock” which means we could start building right away. To make

our robot functional we need also build some custom parts. These custom parts are simple

enough for us to manufacture on our own and they are using aluminum sheet as material.

Anodized aluminum sheet costs around 13€ per 200x1000mm sheet.

The control electronics needed to drive the RC servo motors will most likely be handed to us from

the Mechanical Engineering laboratory. Which means that our rough budget estimate would be

between 200€ to 400€ - mainly depending on the servos we decide to use and whether we

manufacture the frame parts on our own or we order them from a third party. However this

budget is just a rough estimate and we need to make it more accurate as we gain better

knowledge what parts we already have at our disposal.

The preliminary budget approved by Panu Kiviluoma can be found below in Table 1. The budget

doesn’t show exact costs for the bulk aluminum required, but we estimate the aluminum and

plastic materials to cost around 50€ to 80€. The prototype will be built with existing Arduino UNO

board and an old mobile phone power supply will work as a power source for the RC-servos.The

electronic components could be changed to achieve a more finished look, but all the necessary

functions will be achieved with Arduino UNO. With these things taken into account the budget

proposal stays at approximately 200€.

Table 1. The original budget proposal missing the estimates for aluminum materials and

electronic parts.

Part name Part code Required (pcs)

Unit price (€)

Total price (€)

Retailer

Actuator arm servo SG-0351 3 20,90 62,70 Hobbyfactory Oy / Leppävaara

Servo mount 306200-K 3 8,90 26,70 Hobbyfactory Oy / Leppävaara

Servo horn (aluminum) ? 3 10,00 30,00 Hobbyfactory Oy / Leppävaara

Ball joints (16 pcs) MC421942 1 7,20 7,20 Hobbyfactory Oy / Leppävaara

Actuator end material m2 0 Protoshop Oy / Otaniemi

Aluminum bar (circle, 5mm) m 1 0 Protoshop Oy / Otaniemi

Aluminum sheet (2 mm) m2 1 0 Protoshop Oy / Otaniemi

Aluminum tube (4x?x?) m 1 0 Protoshop Oy / Otaniemi

Aluminum square profile m 1 0 Protoshop Oy / Otaniemi

Threaded rod 3mm ZN m 2 0 Protoshop Oy / Otaniemi

Total expenses (€ ) 126,60

4.4 Actual budget based on purchases

In this chapter we will go through all the expenses that were caused by the project so we can get a

clear idea of how much the robot cost in the end. We decided to manufacture all the frame parts

on our own for two reasons. First we wanted to save money as we wanted to keep the budget as

low as possible – we wanted to challenge ourselves to make a cool, finished looking prototype

with the minimum amount of money. Secondly we wanted to learn manufacturing and machining.

We had also to change the originally planned ball joints as there were some problems with the

supplier. We changed them to slightly more expensive ones, but the price difference was only a

few euros. The true costs of the project are shown in Table 2.

Table 2. The true costs of the project.

Part name Unit price (€)

Total price (€)

Retailer

Aluminum sheet 1.5mm

9,90 / kg 27,72 Protoshop

Aluminum beam 6.0mm

12,00 / kg 1,20 Protoshop

Aluminum tube 6x1.0mm

1,00 / m 1,00 Protoshop

Threaded Rod 3mm ZN 1,35 / m 4,05 Protoshop

Threaded Rod 4mm ZN 2,20 6,60 Protoshop

Aluminum square profile 10x10mm

10,00 2,80 Protoshop

Aluminum square profile 20x20mm

9,50 4,56 Protoshop

Polyacetal d=200mm 14,63 / kg 23,41 Protoshop

Cutting service 2,00 2,00 Protoshop

Savöx SG-0351 4.1kg/0.17 Digital Servo

20,90 /pc 62,70 Hobbyfactory

Aluminum servo horn , HUDY

11,90 / pc 35,70 Hobbyfactory

Aluminum servo mount , Xray

9,90 / pair 29,70 Hobbyfactory

Ball joints , Traxxas 11,40 / 12 pc

11,40 Hobbyfactory

Savöx SC-0251MG 16kg/0.18 Digital Servo

41,90 /pc 125,70 Hobbyfactory

Total costs (€) 338,54

5 Kinematics

In this chapter we will look through the mathematics for solving the angles of the servo motors in

situation where we know the point of the delta robots actuator end. This is the situation, when

we are setting a desired point of the actuator end and then driving each servo motor to a

corresponding angle. In order to make the equations more simple we will calculate all required

servo angles separately – just modifying the calculation of motors 2 and 3 by rotating the

coordinates 120° or -120° accordingly (rotation around z-axis). The rotation is done with basic

rotational matrices. To begin with we set the coordinates as shown below in Figure 5. The y-axis is

aligned with the first servomotor’s upper arm, thus setting angle of the servo in the yz-plane.

Figure 5. Coordinates for the first servomotor.

First we need to declare the movement of one arm. The structure of the arm consists of bars,

hinges and ball joints – which can be reduced to two bars connected with a ball joint, in terms of

mathematics. The simplified structure of one arm is shown in Figure 6. The upper part of the arm

(1) is moving only in the yz-plane, because the movement of servo motor is limited only in rotation

around its x-axis. The lower arm (2) can rotate in yz-plane and also move in x-axis direction. The

highest bar of quadrangle has to be parallel to x-axis, because joint B is hinge. This means that – if

lower arms are set properly – the lower bar will also stay almost parallel to x-axis. The result is that

the actuator end (3) of the delta robot has to stay parallel to the xy-plate. This means that the

structure is indeed self-balancing as shown earlier by the CAD-model.

Figure 6. Simplified structure of one arm of the delta robot.

First we solve α1 (angle of servomotor 1) based on the point coordinates we want the actuator end

(point E in Figure 5) to be in. The known points are E (the target), the distance between E and C

and that the actuator end stays always parallel to yz-plane, thus meaning that the vector between

E and C stays always parallel to y-axis. Also the point A is known as it is defined by the structure.

The length of vector from origin (O) to A describes the distance of the servo motor axis to the

center point of the top plate. Also the length of the vector from point B to C is equal to the length

of the lower arm.

We also know the lengths of parts 1 and 2. To get the angle of the servo motor we need to solve

the coordinates of the point B. To calculate B, we also need to calculate the coordinates of point

D. The used markings for the coordinate points are shown in the following Table 3.

Table 3. The points used in calculating the required servo angles α1, α2 and α3.

Entity name

Description Known value A (xA, yA, zA) = (0,yA, 0) yA = -77

B (xB, yB, zB) = (0, yB, zB)

C (xC, yC, zC) = (x0, y0-EC,z0) EC =39

D (xD, yD, zD) = (0, y0-EC ,z0) EC =39

E (target) (x0, y0, z0) Driven value

AB (length) r1 r1 =211

BC (length) l2 l2 =332

As it can be seen from figures 5 and 6 point B lies in the intersection point of two circles. The origin

for the first circle lies at point A (in yz-plate), whose radius is the length of the part 1 – this

describes the possible movement of the upper arm. Origin of the second circle lies at point D. The

radius (r2) of the second circle can be understood as a projection of the length l2 to the yz-plane.

This can be calculated as the vertical part of the vector from B to C. This can be done with the

basic Pythagorean theorem. The calculation of the projection length r2 is shown in equation 1.

√

(1)

Now that the radius of the second circle is known, we can go on to solve the intersection of these

two circles. The circles are now in the yz-plane as the vector from B to C is projected to yz-plane.

The intersection points for these two circles can be calculated by using the equations 2 and 3 and

then using the solving method shown below. The equations give us two possible values for yB and

one value for zB. We should select the smaller value for yB for the point B (0, yB, zB). The required

angle for the first servo can be then calculated as both points A and B are known.

(2)

(3)

(2.1)

(3.1)

(2.2)

||*-1 (3.2)

Combining equation 2 and 3 gives us:

(4)

From this, we can solve the value for zB:

(5)

where a and b are

Then equation 2.2 can be expressed as follows:

(6)

(7)

This can be then solved by using the basic solving method for second degree equations:

√

(8)

Where

(9)

and (10)

Now

(11)

(12)

and

(13)

To make the programming part more sensible we have to first check if the two circles even have

intersection point. This can be done by examining the discriminant in equation 10. If the value D is

bigger than zero, there is two real number solutions for yB, if D is smaller than 0, there is no real

number solutions for yB and if the value D = 0 there is one real number solution for yB. In order not

to break the robot structure or servo motors we want to stay in the area where there are two

possible solutions to yB. We chose smaller value of yB. Theoretically the point where there is only

one real number solution to yB (D = 0) is also reachable as the circles are just touching, but in

practice there is a risk of lock-up in these points. Thus we do not want to drive our robot to these

points.

(14)

After we have checked that the coordinates, we are driving the actuator end into, are possible, we

can go on to calculate the exact y coordinate of point B (yB). X-coordinate of point B is zero as

defined earlier and the z-coordinate zB is calculated in equation 5. By definition yB is now either:

√

(15)

or

√

(16)

We choose to use the smaller value of these two as described earlier.

Now that we know points A and B, we can determine the angle of the vector AB relative to the

selected 0-line. Now we choose the zero line to be in the xy-plane, so that when the angle value is

negative, servo arm is pointing towards the actuator end (zB < 0) and when the angle value is

positive, the servo arm is pointing away from the actuator end (zB > 0). 0-line being, when the

servo arm is parallel to the top plate (zB = 0).

Now we can determine the angle α1 as follows:

(17)

Now value of zB determines the sign of α as described below, if zB < 0, α < 0.

The same operations must be done to the two remaining servo motor angles. The simplest way of doing this is by multiplying the desired actuator end point coordinate E = (x0, y0, z0) with rotational matrix Rz(ϴ). The rotation is done around z-axis, so

[

] (18)

where angle θ is the desired rotation angle around z-axis.

This gives us the point E in the second servo motor’s coordinate system to be:

and for the third servo motor:

It can be seen that the all the solved equations remain the same, and only the coordinate values

related to point E are changed. This means that the same code can be used to solve all the angles,

only using the point E2 for the second servo motor (counter clockwise from the first motor) and

the point E3 for the third servo motor (clockwise from the first motor).

This calculating method is conducted based on the examples from the links below. This is only one

solution for the kinematics of a delta robot and the kinematic problem can be solved in a

numerous different ways. However this way of thinking is quite easily understandable and it can

be modified into a quite efficient code for micro-controllers and PC to solve. This directly

contributes to the operating speed of our delta robot.

http://forums.trossenrobotics.com/tutorials/introduction-129/delta-robot-kinematics-3276/

http://www.cim.mcgill.ca/~paul/clavdelt.pdf

5.1 Code for the robot

The logic for the code is basically done as the step by step solving of the delta robot’s kinematic

problem described in chapter “Kinematics”. To make the code more efficient there are a few

benchmark points written to make sure that the code stops as soon as it can be seen that the

destination point E is unreachable by the robot. There are also basic safety limits for the point E

written to the code in order to prevent any damage to the robot structure or electronics. One of

these benchmark points is the determination of discriminant D. If D <= 0 the code returns value

“false” for the servo angle thus stopping the robot from moving to the described point. The same

method is used with the set safety limit points. If even one of the servo motor angle calculating

functions returns value “false”, the code stops the robot from driving even the other servo motors

to that target point E. The basic idea behind the code is that we do all the calculating on PC, and

leave the on-board microcontroller (ATmega328 in Arduino UNO) only work as an interface

between the RC-servomotors and the PC. The communication happens through USB –serial port,

and as ATmega328 can only work with int() –type of variables and values, the desired angle is

given between 0 and 180 degrees. The desired angle is translated to PWM –signal for the RC-

servomotors by microcontroller.

The translator and the basic delta robot controlling (incl. calculating angles) are two different code

sets. Communicating between Arduino and PC proved to be little bit challenging. The Arduino Uno

serial buffer size is 64 bytes and in some cases the buffer size is not enough big. Overloading of the

buffer will mess the information between the driven RC-servos. Overloading causes the

information of one servo motor to go on to wrong servo motors, which then caused irrational

behavior of the robot. This can’t be seen, when the actuator is driven only in the z-direction (y=0,

x=0), but when x- or y-value differs from zero, the incorrect PWM-signal per RC-servo motor can

be seen clearly. There are few ways to solve this problem. We decided to limit the amount of the

data, which is send to the microcontroller. Robot’s controlling program is sending data only if the

coordinates are changed, in the meanwhile microcontroller is generating PWM-signal based on old

values. Generating PWM-signal whole time is essential to keep the positions of the RC-servos.

To create the user interface Processing language is used. Processing was chosen because of the

serial communication library and the library for the joystick. A good documentation and the

libraries used made it easy to make communication between PC and Arduino, and also between

the program and the joystick. The drawback of using the Processing was amount of work to create

the graphical user interface. The user interface of the controlling program is presented in figure 7.

In the top-left corner of the UI-window shows the basic functions for the drive: desired coordinate

points, toggle for drive (on/off) and driving mode (upside down –button). Clicking over the

pictures will change the values. Coordinates can be decreased by clicking the left side of picture

and by clicking the right side the coordinates will be increase. Coordinates can also be driven with

a joystick or through the predefined automated routes. Some helpful data is presented in the

bottom-left corner. The color of the possible mark tells if the coordinates can be reached by the

delta robot and the angels of upper arms are presented next to the possible signal. The different

predefined routes can be chosen in the top-right corner. First route is basic circle driven half-

automatically. The radius and the z-coordinate of the circle can be changed during the movement.

The route1 is programmed to draw a logo of the Aalto university (can be seen in the figure 8) and

the route2 is drawing third degree equation and a coordinate system for the graph. In the bottom-

right corner the location of the actuator end is presented (xy-plane). The robot can also be driven

with the joystick. The code is made to the Microsoft’s SideWinder Precision 2 joystick, but by

minor changes to the code also other joysticks can be used. The joystick enables basic controlling

of the delta robot, included different gears, which make it possible to drive the delta robot at

different speeds.

Figure 7. The graphical UI-window for the delta robot.

6 Physical structure

We decided to manufacture all the custom parts by ourselves for two reasons: firstly we wanted

to see how cheap we can build a working robot and secondly we wanted to learn basic

manufacturing skills. The fact that we decided to manufacture everything by hand also gave us the

freedom to change the design details as we went on. To make the robot more adjustable, we

chose to change the design for the bottom of the legs with adjustable leg ends so that we didn’t

require flat surfaces to mount our robot on. We also changed the design for the actuator end so

that we could attach different actuators to the actuator end mounting point. The adjustable

actuator end was simply done with a 3 screw mechanism working in the same sense as the basic

milling machine tool holders. The picture of our first version of the mechanical structure of a delta

robot can be seen in figure 8.

Figure 8. The actual first physical prototype of our delta robot.

Based on the physical delta robot prototype we found out that we cannot reach as large area as

we had thought based on the CAD-model. However we had anticipated this and designed the

robot dimensions so that there is large enough tolerances to still reach the area (d = 30 cm) we set

as our goal. The reason we are not able to reach the dimensions our CAD-model pointed, is that

we couldn’t take the mechanical restrictions of the ball joints into account, when we were building

the CAD-model. However we knew this, when we were building the model, so it didn’t come as a

surprise that the actual area we are going to reach is smaller than what the CAD-model predicted.

The actual are we area going to reach is approximately d = 30 cm. The first tests driving the robot

also proved that the RC servos we had chosen were too weak for our purposes. This could have

been prevented, if we had spent a little more time with the CAD-model and conducted some

simple force measurements. However the weaker servos we used were cheap, so it was only a

minor setback to the project.

The physical prototype also pointed out that even though the frame legs were quite rigid on their

own, the actual frame portal was a bit too flexible for the robot to be as accurate as possible.

However we set out to demonstrate the capabilities of delta robots and to create a futuristic and

thought out looking robot and this is what we achieved. For further improvements the frame

should be redesigned to maximize the structural rigidity to form the best possible platform for the

robot actuators.

7 Summary

In the end we were able to reach our goals we set to our project in the beginning of this course.

We were able to create a finished looking prototype of a delta robot and we were able to

demonstrate the capabilities of delta robots at the Mechatronics Circus. We used the robot to

draw Aalto University logo based on an automatic route. We also implemented a manual drive and

some half-automated routes for the robot to run. These routes and functions were chosen

because we wanted to point out that robots are part of industrial automation rather than

manually driven tools. We incorporated the manual drive to the final prototype to demonstrate a

safety feature for an industrial robot in a case where the robot gets stuck or something else goes

wrong. The manual drive also proved to be quite a hit amongst the Circus visitors. Despite the

small setbacks throughout the project we can still say that this delta robot project was successful.

As it can be understood by reading this report, we didn’t sail through the project without

problems. The biggest issue during the project was the communicational problems to get the

Arduino board and the PC-program to communicate effectively and without any problems. There

were also some minor issues with the electronics, mechanical design and the fact that we couldn’t

get the third aluminum servo horn in time for the Circus. The mechanical design was still good

enough for us to demonstrate the capabilities of delta robots.

If we were to start over or get involved into a new development process of a delta robot, we

would want to make the virtual prototypes more accurate to get rid of all possible errors in the

design. Virtual prototypes are cheap and the changes at this stage doesn’t cost anything but labor.

Other than that we should choose better microcontroller and driving servos as well as more

accurate ball joints to make the robot more stable and more effective. Other than that, the timing

of the project went rather well and we met all the major goals, we set for the project.

Sources

1. Matt Greensmith’s Ramblings. Making an Arduino-controlled Delta Robot. 2011. [Referenced

2.5.2014]. URL: http://mattgreensmith.wordpress.com/2011/11/26/making-an-arduino-

controlled-delta-robot/.

2. Trossen Robotics Community. Delta robot kinematics. [Referenced 2.5.2014]. URL:

http://forums.trossenrobotics.com/tutorials/introduction-129/delta-robot-kinematics-3276/.

3. Zsombor-Murray, P. J. Descriptive Geometric Kinematic Analysis of Clavel’s “Delta” Robot.

2004. [Referenced 2.5.2014]. URL: http://www.cim.mcgill.ca/~paul/clavdelt.pdf.