P10203 LV1 MOTOR CONTROLLER

FINAL REVIEW

MAY 14, 2010

Electrical: Kory Williams, Adam Gillon, Oladipo Tokunboh Mechanical: Louis Shogry, Andrew Krall

Agenda Project Overview Customer Needs Design Specifications Project Status Schedule Budget Testing Results Issues and Findings Conclusions and Future Work

Project Overview The purpose of the LV1 motor controller

project was to reduce the cost of the previous generation RP1 motor controller while also improving size, manufacturability and appearance.

Our team was to work closely with the other coincident LV1 projects (P10201, P10202, P10205) to create a functional robotic land vehicle with the capability to transport a 1 kg payload.

Customer Needs The controller is easy to manufacture and assemble. The controller is modular, (can be configured in several different options

to support varied functionality). The controller has a low risk implementation and is stand-alone. The controller is able to properly interface with the other modules of the

Land Vehicle Platform. The controller is able to be used by first year mechanical/electrical

engineering students. The controller is able to make the platform move with sufficient agility

and controllability. The new design shall improve upon the aesthetics of the RP1. The controller makes effective use of the space provided by the Chassis. The new design is cost effective, (cheaper than the RP1 with the same,

or improved performance characteristics). The controller is durable and can withstand repeated use with minimal

maintenance. The controller has a reasonable battery life. The controller is able to be upgraded by future Senior Design teams

with little redesign or component replacement needed. The controller makes use of Prior Generations Designs and Research.

Design SpecificationsEngr.

Spec # Customer Need Specification Unit of Measure

Marginal Value

Ideal Value Comments

ES1 CN9, CN13 Total cost of Controller. $ $475.00 $400.00 Reduction from $511 in RP1ES2 CN5, CN10 Mounted Controller drop test surviveability. Feet 3 5 Based upon table-top fallES3 CN3, CN10 All sensitive components are separated from Noise Centimeters > 4 cm > 8 cm Will conform to available dimensionsES4 CN4, CN7, CN8 Distance between controller outputs and interfaces. Centimeters < 30cm < 15cm Will conform to available dimensions

ES5 CN10 Operating Temperature of Components in Controller.Degrees Celcius

125 C 100 CMaximum temperature of any individual component in the system. This is the junction temperature inferred from the outer temperature of the case.

ES6 CN4, CN12 Amount of memory on controller. KB 75kB 50kB 50kB is about 40% of the available memory on the controller.

ES7 CN4, CN12 Number of I/O able to be controlled. Count 14 20 Quantification of all inputs and outputs to/from the system

ES8 CN4, CN6, CN12 Bandwidth required at input to controller. Data Rate 50 Kbps 250kbpsBased upon available data rate range of wireless technology used by P10205

ES9 CN4 Data Format at Input to Controller. Format 8N1 Bits 8N1 Bits Dictated by onboard software from RP1ES10 CN4, CN12, CN13 Programming Language used to program Controller. Language C++ C, C++, ES11 CN4, CN6 Latency of Command Throughput. ms 150 ms 100 ms Time required to process input and output control signals

ES12 CN6 Degrees of Freedom maintained by Controller. Steering, 2 2

ES13 CN4, CN6 Controller interfaces with motor modules independently. Boolean 1 1

ES14 CN11 Power Consumption of the Processing Sub-system. Watts < 5W < 3WThis value refers to the power consumption of the entire controller. This does not include the consumption of the motor modules.

General Design

Processing Subsystem

Correction Subsystem

Motor Driver(s)

Power Distribution Subsystem

System Architecture

Product Development Process

Phase 0: Planning•Define Project Goal•Develop Customer Requirements•Define Engineering Metrics

0

Phase 1: Concept Selection•2 Rounds of PUGH Concept Selection•Analysis of existing RP1

1

Phase 2: Product Design•Pspice Simulations•Validation using engineering calculations

2

Phase 4: Building•Order parts•Assembly and mounting

4

Phase 5: Testing•Subsystem•Interfacing

5MSD 2

Phase 3: Final Design•Detailed Schematics and Layout•Finalized BOM

3MSD1

Current State

Project Status Controller is able to function independently

of the other modules on the LV1 platform. Controller is able to communicate over the

Wireless communications link with the GUI. Controller is able to drive all four motors at

the same time (unmounted) Battery is compatible with regulation circuits

on the controller.

Schedule Interface testing with Wireless team

completed on schedule. Interface testing with Chassis and Motor

Modules fell behind 2 weeks. Full System testing is still incomplete.

Final tests will be run when the platform can be run on the ground.

Budget Total Cost of Two Controller Units is

$798.00 including shipping for parts and components. (20% reduction from the RP1).

Total cost does not include encoder cables that were purchased late due to a miscommunication with the motor module team.

Some components like the mounting plate for the PID controller can be removed from BOM since they were not used.

Testing Results Subsystem Testing Voltage Regulator boards are functional and able to

limit an 8.4V input to 5V (Logic) and 5.93V (Servo). Motor Driver boards are able to amplify a PWM

input signal and provide the stall current condition (1.6A). FWD/REV and speed control are confirmed.

I2C interface between Control Units is confirmed and communications between the devices has been established.

Controller interfaces with the GUI via a wired connection.

Testing Results (cont) Interface Testing• Communications with the Wireless Team has been

established using the GUI to send motor control commands.

• Using the GUI, we are able to move the drive motors bidirectionally and with varied speed. Servos are also able to be rotated 180 degrees.

• Battery successfully powers up regulator circuits and provides enough voltage to maintain constant Logic and Servo Levels.

• Encoder Functionality has not yet been evaluated since motors cannot be driven in contact to the ground.

Issues and Findings As a subsystem, the controller can operate as

intended in the design. Full System Integration has not yet been

established since we are unable to move the robot on the ground.

When the motors try to overcome static friction, there is a large risk of permanent damage to both the drive motor and the motor driver circuitry due to a large current draw. Current limiting circuits may be required in order to obtain proper control of the platform.

Conclusions and Future Work There are some additional layout issues that can

be resolved to make external connections easier.

The thermal coating considerations were dropped due to time restrictions and limited resources.

Additional software knowledge is required for alteration of GUI or program of MCU Unit and PID Controller.

Linear Regulators could be replaced with switching regulators to reduce power loss.