control system project

Linear Motion Actuator with Feedback Control

Item	Remarks	Points	Score
Phys model	Diff equations done correctly? Is frequency response addressed?	25
Motor model	Is motor sized correctly?	25
Elect ckts	Will circuits work?	25
PID operation	Does the system respond to spec?	25
SS operation	Does the mechanical design make sense?	25
Mech design	Position, speed, current, motor, etc.	25
BOM, datasheets	Position, speed, current, motor, etc.	25
Safety	I and V limits, total force at cart, etc.	25
O/A quality	Readable, figures legible? Citations? Figures, tables, equations numbered? Organization good? Anything haphazard, or unclear?	100
		Total /300

( Scoring sheet (for instructor use) )

Linear Motion Actuator with Feedback Control

Scope

The student/group will design, model, simulate, and specify all components necessary to build an electric motor driven linear actuator and cart system.

Purpose

The cart system is to be capable of safely demonstrating a wide range of responses to various inputs under different loading conditions. The control scheme is to be switchable between analog and digital operation.

Specifications

Electrical

The prime mover is to be a voltage controlled DC motor, either 12 VDC or 24 VDC.

Feedback sensor and control signals shall be limited to ±10 VDC.

Loading

The total weight of the cart (the moveable portion) is to be between 10 and 20 pounds (lb_f).

Feedback Signals

Provisions shall be made to obtain position and velocity signals for display on an oscilloscope or as feedback signals for control purposes.

Position:

The position feedback signal shall be obtained by two different methods: a rotary encoder on the motor; and a magnetostrictive linear transducer mounted on the cart travel mechanism. Provisions should be included to allow acquisition of data from both devices.

Velocity:

The velocity signal may be obtained using the same motor encoder as used for position feedback. Optionally, the velocity may be obtained using an accelerometer, or any other suitable measurement device that is found to be available.

Portability

The system shall be one complete unit with all permanent components mounted on the same chassis. Total weight of the complete system shall not exceed 50 lb. The overall size of the complete system shall not exceed 12 x 20 x 36 inches.

Travel Limits and Dynamic Response Requirements

Position:

The linear travel shall be no less than 12 inches.

Velocity:

Report is to address maximum speed predictions and discuss safety considerations and possible speed limiting design features.

Acceleration:

Demonstrate through simulations the maximum expected values for acceleration.

Dynamic response:

The system shall be capable of operating as underdamped, critically damped, and overdamped in response to a step input. At least one controller must demonstrate settling time of 1.5 seconds or less in response to a step input of 3 inches, using maximum cart mass. Compare that response with the response using the minimum mass.

Control

The control board shall be designed to allow easy conversion between analog and digital control systems. Digital control will be achieved using Simulink or similar software. The analog control board should allow P, PI, PID, and State Feedback control operations. Include diagrams for implementation of various controllers using resistors, capacitors, and operational amplifiers.

Safety

The motor shall allow stalling without damage.

Determine the maximum force tending to push the cart when the motor is stalled, and comment on the associated operator safety issues.

Report

Format

Use the cover sheet as seen on the first page of this document. Follow the formal Lab Report Guidelines found on the course website.

Drawings

Mechanical:

Schematic assembly drawings showing the positions of all components are required and may be produced either by hand or by computer. Detailed mechanical drawings are not required.

Electrical:

Provide all circuit diagrams (hand sketches are sufficient) of P, PI and PID controllers using analog components. Specify the values of all components for an analog PID controller design that produces a nearly critically damped cart position step response. Use capacitors rated from 0.01 to 0.1 microfarads.

Purchased Part Specifications

Produce a Bill of Material of all required items. Provide manufacturer’s data sheets on all purchased components.

Analyses and Simulations

· Provide complete mathematical modeling of the system and its components (free body diagrams and differential equations are required).

· Provide a complete Laplace-domain block diagram of the system and its components.

· Provide simulations for step responses and sinusoidal input responses under pertinent controller and loading options.

· Demonstrate that all position, velocity, acceleration, voltage, and currents comply with the constraints imposed by the devices selected.

· Indicate the natural frequency and bandwidth of the motor, the load, and the closed loop system with the PID controller that provides a nearly critically damped response.

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