Hydraulic Modular Articulated Robot – Preliminary Design

ME481 Group 3Abed Alnaif

4A Mechatronics EngineeringUniversity of Waterloo

October 6, 2008

Hydraulic Modular Articulated Robot

Introduction

Articulated robot is a series of links connected by rotary joints

Hydraulic Modular Articulated Robot

Needs Assessment / Problem Formulation

Articulated robot that is modular and extendable Modules are identical Length of robot is easily customized by

adding or subtracting modules Modules need to be able to support rest

of the robot

Hydraulic Modular Articulated Robot

Problem Definition

Goals: Have 2-module prototype built Have control algorithm developed

Objectives: Accuracy of control Compact size

Hydraulic Modular Articulated Robot

Constraints & Criteria

Constraints: $1500/module Capable of lifting 60 kg with 2 modules Capable of supporting at least 10 modules

Criteria: Size Load Capabilities Controllability (ease and accuracy of

control)

Hydraulic Modular Articulated Robot

Current Technologies & Patents

Current modular robots are built from electrical actuators Low power-to-weight ratio

Hydraulic Modular Articulated Robot

Current Technologies & Patents (2)

Modular, reconfigurable robots

Hydraulic Modular Articulated Robot

Current Technologies & Patents (3)

Snake-arm robot

Hydraulic Modular Articulated Robot

Current Technologies & Patents (4)

Patent 6323615, titled “Modular Articulated Robot Structure” Vague Published 02/03/2004

Hydraulic Modular Articulated Robot

Advantages of Hydraulics

Helac Hydraulic Helical Rotary Actuator

Weight = 6 kg

Nominal output torque = 190 N-m

100 mm

140 mm

Amtec Servo Motor and Gear Box

Weight = 3.2 kg

Nominal output torque = 45 N-m

180 mm

90 mm

High Power Density

Hydraulic Modular Articulated Robot

Advantages of Hydraulics (2)

Micromatic Vane Hydraulic Rotary Actuator

Weight = 9.75 kg

Nominal output torque = 773 N-m

124 mm

195 mm

High Power Density

Hydraulic Modular Articulated Robot

Advantages of Hydraulics (3)

Easily customizable mechanical advantage Force = Pressure * Area Velocity = Flow / Area

Ease and accuracy of control Ability to lock position of modules

Hydraulic Modular Articulated Robot

Disadvantages of Hydraulics

Need to use valves Oil leaks Noisy

Hydraulic Modular Articulated Robot

Conceptual Designs

2 Rotary Actuators

Hydraulic Modular Articulated Robot

Conceptual Designs (2)

2 Rotary Actuators Reconfigurable

Hydraulic Modular Articulated Robot

Conceptual Designs (3)

3 Cylinders Can rotate, as well as extend the

next module

Hydraulic Modular Articulated Robot

Challenges

Achieving compactness Routing of hydraulic hoses Controls

Nonlinear Effects of positioning one module on

other modules (Action / Reaction Forces) Funding

Hydraulic Modular Articulated Robot

Questions?

Questions?