CE110 Servo Trainer

Features

Supports a wide range of control principles at all academic levels, including controller design and velocity (rate) feedback

Facilities to vary load, inertia, deadzone (deadband), saturation and hysteresis Calibration of system components supports analytical approach to solving control problems Simple front panel layout Control element may be an analogue or digital computer All inputs and outputs buffered for direct and safe coupling to external control element Dedicated menu driven software with virtual instrumentation MATLAB compatible data file format Supplied with comprehensive experimental manual Two year warranty Complies with the latest EEC Safety Directives

Description

The CE110 Servo Trainer Apparatus is one of a unique range of products designed specifically for the study and practical investigation into basic and advanced control engineering principles. This includes the study of static and dynamic systems using either analogue or digital techniques.

The CE110 Servo Trainer Apparatus relates to d.c. servo position and speed control systems using typical industrial techniques. It may also be used as a flexible tool for the practical introduction into the design, operation and application of controllers in general.

The apparatus comprises a d.c. servo motor, a d.c. generator and a flywheel mounted on a common shaft.

An analogue input signal to the motor circuit in the range 0 to 10V enables variable shaft speed of rotation in either direction to be achieved. Shaft speeds, up to 1999 RPM, are continually sensed optically and indicated on a panel mounted digital meter. An analogue signal proportional to speed, in the range 0 to 10V, is available at an adjacent socket. The motor may be loaded, statically or dynamically, using the d.c. generator. The full range of loads may be applied by inputting an analogue voltage in the range 0 to 10V at the appropriate socket. This electronically varies the load on the generator.

The CE110 is supplied with two additional interchangeable inertia discs which may be added to the flywheel. Access to the flywheel to achieve the inertia variations is via an interlocked hinged cover at the rear of the unit. This ensures that no power to the motor is obtainable should the cover be open and, hence, user safety assured.

An electrically operated clutch, enabled by a toggle switch, engages an output shaft via a 30:1 reduction gearbox such that position control performance may be investigated. A scaled dial indicates actual shaft position in the range 0 to 170 and a 2000 pulses per revolution incremental shaft encoder provides an analogue output signal in the range 0 to 10V corresponding to a shaft position of 0 to 180. An adjacent dial may be set manually to provide a demand signal for closed-loop positional control of the shaft.

In addition to the main rotating components, a further facility for investigating servo-mechanism control is provided in the form of a set of typical servo-system non-linear elements. Non-linearities may be introduced into the control system to both investigate their detrimental effects on motor response and performance as well as illustrating techniques for their correction. These elements are of vital importance in the study of servo systems because they introduce typical system parameters which occur in practice. The block elements are electronic circuits which are situated and accessed along the top of the front panel. The elements are;

Anti-Deadzone Block

This element performs the function of a deadzone, or static friction, compensator and may be used to eliminate the actual deadzone of the servo motor itself or the additional effects set by the Deadzone Block. A panel mounted rotary potentiometer may be set in the range 0 to 5V to produce static friction compensation of 0 to 5V at the output to the element.

The element may be switched into or out of the circuit using an In/Out toggle switch. Input to the circuit is at a panel mounted 2mm socket, in the range 0 to 10V, and the modified output is to the Deadzone Block.

Deadzone Block

This element allows the practical feature of servo drive amplifier deadzone to be electronically simulated and studied. A panel mounted rotary potentiometer may be set in the range 0 to 5V to provide static friction which may be offset by 0 to 5V. The element may be switched into or out of circuit using an In/Out toggle switch. Input to the circuit is from the previous element, the Anti-Deadzone Block, and output is to the Saturation Block

Saturation Block

This element allows the practically important feature of servo-drive amplifier saturation to be simulated and modelled. A panel mounted rotary potentiometer may be set in the range 0 to 10V to provide saturation of 0 to 10V. The saturation level set effectively limits the maximum supply voltage to the servo motor and, hence, the power it can deliver. The element may be switched into or out of circuit using an In/Out toggle switch. Input to the element is from the previous element, the Deadzone Block, and output in the range 10V is to a 2mm socket.

The output from the Anti-Deadzone Block, Deadzone Block and Saturation Block chain is determined by the original input value and the combined effects of each element. This effect would normally be connected to the output of a controller to simulate practical servo system performance.

Hysteresis Block

This element enables the practically important feature of gearbox and servo-drive train backlash to be simulated and studied. This may be used in conjunction with the other elements or independently to provide the performance required. A panel mounted rotary potentiometer may be set in the range 0 to 10V to produce hysteresis at the output of 0 to 10V. Input and output to the block is at 2mm sockets for connection to the control system.

The base of the CE110 contains all of the power supplies, amplifiers and signal conditioning circuits to ensure that it is a self-contained unit. These circuits are buffered against overload and short circuit.

The CE110 is designed to operate with an external controller, the CE120 Controller for analogue or digital control or alternatively the CE122 Digital Interface for digital only control. A further option is for control to be achieved by users supplying their own compatible analogue or digital controller. Adapters are supplied to enable the CE110 to be connected to most commonly found laboratory equipment.

The CE110 Servo Trainer is supplied with a comprehensive operating manual which gives full details of the apparatus, the relevant control theory and a set of recommended experiments. Typical results are included.

Dedicated software is included for controlling the CE110 using an IBM PC, or 100% compatible, via the CE120 Controller or CE122 Digital Interface. The package is a menu driven program suite which allows the user to interactively investigate various aspects of digital servo control. The on screen options allow for various control system configurations to be set up and then run in real time. Virtual instruments display the relevant system parameters in digital and graphical formats. Experimental data may be saved, processed or output to a printer to provide a hard copy of results. The data files are saved in a format which allows them to be input to a wide selection of text editing and spreadsheet software packages, including dedicated control applications such as MATLAB. The software is supplied with a manual describing the functionality of the software as well providing typical experiments.

Range of Experiments

An extensive range of experiments may be carried out with the CE110 Servo Trainer Apparatus. The experiments included in the manual supplied with the CE110 have been written assuming that it is used in conjunction with the CE120 Controller. These can be modified to suit any alternative controller.

Experiments included in the manual are,

For servo speed control;

1. Perform Basic Tests and Transducer Calibration

2. Response Calculation and Measurement

3. Proportional Control of Servo-System Speed

4. Proportional plus Integral Control of Servo-System Speed

5. Disturbance Cancelling and Feedforward Control

For servo position control;

6. Angular Position Control: Proportional Control

7. Angular Position Control: Velocity Feedback

8. Angular Position Control and the Influence of Non-Linearities

9. Non-Linear System Characteristics

Guidance and typical results are included in the manual to assist supervisors in the preparation and marking of student assignments.

The experiments given in the manual are intended as an introduction into the major aspects of experimentation into servo-control systems and techniques. The flexible design of the equipment enables many other analysis and control exercises to be developed and performed by the user to suit local requirements. This includes extended or advanced control experiments as well as being ideal for student project work.

Ancillaries

The CE110 Servo Trainer Apparatus is designed to be monitored and controlled by a compatible external controller, either analogue or digital. The CE120 Controller and the CE122 Digital Interface have been designed to provide all of the facilities required by the CE110 and the other apparatus in the TecQuipment Control Engineering Range. Since all of the power supplies for the built-in devices and systems are included, only low power connections between the CE110 and the external controller are required.

The following listing details the recommended ancillaries for the CE110:

CE120 Controller:

Provides fully compatible control and monitoring facilities for the whole TecQuipment Control Engineering Range, analogue and digital, via circuits accessed at 2mm sockets mounted on the front panel.

Analogue facilities include potentiometers (4), summing amplifiers (4), proportional amplifiers (4), integrators (3), phase lead network, a three-term controller, a function generator and a d.c. power supply. These may be interconnected in any combination to produce the required system performance.

Digital facilities include an RS232 interface so that 12 bit analogue inputs (8) and 12 bit analogue outputs (4) are available at the appropriate front panel sockets. These are directly accessed and controlled by an external computer. The minimum requirements for this being an IBM AT 286 computer, or 100% compatible, VGA, a hard disc and an RS232 serial port. It is possible, therefore, to affect the performance of the CE110 under the control of the software packages available. Supplied with general purpose control and data acquisition software and operating manual.

See separate Data Sheet for further details of the CE120.

CE122 Digital Interface:

The CE122 is a digital only control option. In specification and operation it is identical to the digital section of the CE120.

See separate Data Sheet for further details of the CE122.

E17C Chart Recorder:

Two channel Yt chart recorder for producing a permanent copy of system transient response.

E32G Oscilloscope:

20MHz dual beam oscilloscope, 1mV sensitivity. For waveform monitoring.

Note. The functions of the E17C and E32G may alternatively be performed using the data acquisition capabilities of the digital section of the CE120, or the CE122, with its included software. The additional benefit is that computer captured waveforms can be saved, processed and output to a printer.

Services Required

Single-phase a.c. 240/110V, 2/5A, 50/60Hz supply, with earth. Please specify requirements at time of ordering. Other voltages and frequencies may be available to special order.

Noise

The measured sound pressure level of this apparatus is less than 70 dB(A)

Space Required

For satisfactory use of this equipment, a bench area of approximately 1m x 750mm is recommended. Experiments may be performed by students working singly or in groups of two or three.

Dimensions and Weights

Nett: 540 x 330 x 420mm; 18.7kg.

Gross: 0.3m3; 41kg. (approx - packed for export)

Tender Specification

A compact bench mounting d.c. servo apparatus to investigate the principles involved in open and closed-loop configurations for position and speed control using an external analogue or digital controller (not included). Facilities to change the inertia, hysteresis, deadzone and saturation included. All rotating components enclosed and low signal levels for operator safety.

Comprises a d.c. servo motor, a d.c. generator and a flywheel mounted on a common shaft. An analogue input signal to the motor circuit in the range 10V enables maximum speed in either direction to be achieved. Shaft speed, up to 1999 RPM, is sensed optically and indicated on a panel mounted digital meter. The speed signal is also available as a proportional analogue signal in the range 10V at an adjacent socket. Static or dynamic loads may be applied to the motor by inputting an analogue signal in the range 0 to 10V at the appropriate socket. Non-linearities may be introduced into the system to both investigate their effects on transient performance and also to illustrate techniques for their removal.

An electronic clutch, enabled by a toggle switch, engages an output shaft via a 30:1 reduction gearbox such that position control performance may be investigated. A scaled dial indicates actual shaft position in the range 170 and a 2000 pulses per revolution incremental shaft encoder provides an analogue output signal

in the range 10V corresponding to a shaft position of 180. An adjacent dial may be set manually to provide a demand signal for closed-loop positional control of the shaft. All power amplifiers and signal conditioning circuits are contained within the unit and are buffered against overload and short circuit.

Dedicated menu driven software included to enable real time digital control using an IBM PC, or 100% compatible via a CE120 or CE122. Data files are saved in a format which may be input to a wide range of text editing and spreadsheet software packages, including dedicated control software applications such as MATLAB.

CE110 Servo TrainerFeaturesDescriptionRange of ExperimentsAncillariesServices RequiredNoiseSpace RequiredDimensions and WeightsTender Specification