Closed Loop Position Mode | RoboteQ AX2550/2850 manual

Mode Description

SECTION 10

Closed Loop Position Mode

This section describes the AX2500/2850 Position mode, how to wire the motor and posi- tion sensor assembly, and how to tune and operate the controller in this mode.

Mode Description

In this mode, the axle of a geared down motor is coupled to a position sensor that is used to compare the angular position of the axle versus a desired position. The controller will move the motor so that it reaches this position.

This unique feature makes it possible to build ultra-high torque “jumbo servos” that can be used to drive steering columns, robotic arms, life-size models and other heavy loads.

The AX2500/2850 incorporates a full-featured Proportional, Integral, Differential (PID) con- trol algorithm for quick and stable positioning.

Selecting the Position Mode

The position mode is selected by changing the Motor Control parameter in the controller to either

•A Open Loop Speed, B Position

•A Closed Loop Speed, B Position

•A and B Position

Note that in the first two modes, only the second motor will operate in the Position mode.

Changing the parameter is best done using the Roborun Utility. See “Loading, Changing Controller Parameters” on page 162.

For safety reasons and to prevent this mode from being accidentally selected, Position modes CAN NOT be selected by configuring the controller using the built-in switches and display.

AX2500/2850 Motor Controller User’s Manual

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RoboteQ AX2550/2850 user manual Closed Loop Position Mode, Selecting the Position Mode

Contents

AX2550/2850 Dual Channel High Power Digital Motor Controller Date Version Changes Revision History Revision History AX2550/2850 Motor Controller User’s Manual Section Section Self-Test Display 104 124 152 What you will need AX2500/2850 Quick Start AX2500/2850 Quick Start Locating Switches, Wires and Connectors Connecting to the Batteries and Motors Connecting to the Batteries and Motors Connecting the R/C Radio Using the Power Control WirePower Control input connected to Action Powering On the Controller Powering On the Controller Prog and Set button status Function Button Operation Parameter Default Values Letter Default Controller ConfigurationChecking and Changing Configurations Default Controller Configuration Connecting the controller to your PC using Roborun Obtaining the Controller’s Software Revision Number Obtaining the Controller’s Software Revision Number Exploring further Product Description AX2500/2850 Motor Controller Overview Technical features Optical Encoder Inputs AX2850 only Technical featuresLow Power Consumption High Efficiency Motor Power Outputs Data Logging Capabilities Advanced Safety FeaturesSturdy and Compact Mechanical Design Connecting Power Connecting Power and Motors to the ControllerConnecting Power Connecting Power and Motors to the Controller Controller Power Two Controller Power Powering the Controller using the Motor Batteries Powering the controller from the Motor Batteries Using a Backup Battery Wire Length Limits Power Fuses Electrical Noise Reduction Techniques Power Regeneration ConsiderationsElectrical Noise Reduction Techniques Overvoltage Protection Using the Controller with a Power SupplyUndervoltage Protection Using the Controller with a Power Supply Connecting Power and Motors to the Controller Basic Operation Input Command ModesGeneral Operation Basic Operation General Operation Selecting the Motor Control ModesOpen Loop, Separate Speed Control Open Loop, Mixed Speed Control Close Loop Position Control Closed Loop Speed ControlSelecting the Motor Control Modes Setting Continuous High Amps Current Limit SettingsContinuous and Extended Current Limitation Temperature-Based Current Limitation Temperature-Based Current LimitationSetting Continuous High Amps Extended Safe Amps Regeneration Current Limiting Surge Current ProtectionProgrammable Acceleration Programmable Acceleration Exponentiation curves Command Control Curves Left / Right Tuning Adjustment Left / Right Tuning AdjustmentExponentiation Parameter Value Selected Curve Parameter Value Speed Adjustment Emergency Shut Down Using Controller Switches Emergency Stop using External Switch Emergency Stop using External SwitchInverted Operation Self-Test Mode Special Use of Accessory Digital InputsUsing the Inputs to Activate the Buffered Output Self-Test Mode General Operation AX2500/2850 Connections Connecting Sensors and Actuators to Input/OutputsAX2500/2850 Connections Connecting Sensors and Actuators to Input/Outputs AX2500/2850’s Inputs and Outputs Signal Type Use ActivatedAX2500/2850’s Inputs and Outputs List and Pin Assignment Pin Wire Input or Number Color Output Signal Description Connecting devices to Output C Connecting devices to Output C Connecting external Mosfet and load to Output D Connecting devices to Output D Connecting Switches or Devices to Input F Connecting Switches or Devices to Input E Show how to wire the switch to this input Connecting Switches or Devices to EStop/Invert Input Connecting Position Potentiometers to Analog Inputs Connecting Position Potentiometers to Analog Inputs Potentiometer wiring in Position mode Connecting Tachometer to Analog Inputs Resistance kOhm Connecting External Thermistor to Analog InputsConnecting External Thermistor to Analog Inputs Temp oC NTC Using the Analog Inputs to Monitor External Voltages Connecting User Devices to Analog Inputs Connecting User Devices to Analog InputsMeasured volts = controller reading + 128 * 0.255 Internal Voltage Monitoring Sensors Internal Heatsink Temperature Sensors Temperature Conversion C Source Code Temperature Conversion C Source Code Connecting Sensors and Actuators to Input/Outputs Use of the LED Display Normal Fault Condition LED MessagesUse of the LED Display Motor Direction Status Normal and Fault Condition LED MessagesPossible Display Motor Comment Fault Messages Fault MessagesNo Control Emergency Stop Self-Test Display Mode Description Mode DescriptionOperation Typical Wiring Selecting the R/C Input ModeOperation Connector I/O Pin Assignment R/C Mode Connector I/O Pin Assignment R/C ModePin Input or Number Signal Output Description Input Circuit Description Supplied Cable Description Supplied Cable Description Cabling to R/C Receiver using Full Opto-Isolation Cabling to R/C Receiver with Partial Opto-Isolation Cabling to R/C Receiver with Partial Opto-Isolation Partial opto-isolation with Channel 3 electrical diagram Powering the Radio from the controller Wiring for powering R/C radio from controller Powering the Radio from the controller Joystick position vs. pulse duration default values Operating the Controller in R/C mode Transmitter/Receiver Quality Considerations Reception WatchdogReception Watchdog Joystick Deadband Programming Command Control Curves Left/Right Tuning AdjustmentJoystick Calibration Automatic Joystick Calibration Activating the Accessory Outputs Activating the Accessory Outputs Using Channel 3 to activate accessory outputs Data Logging in R/C Mode Data Logging in R/C Mode Operation Use and benefits of RS232 Serial RS-232 Controls OperationUse and benefits of RS232 Serial RS-232 Controls and Operation Connector I/O Pin Assignment RS232 ModeMust be wired to pin 13 or pin Must be wired to pin Cable configuration Cable configurationExtending the RS232 Cable Bits/s, 7-bit data, 1 Start bit, 1 Stop bit, Even Parity Communication SettingsEstablishing Manual Communication with a PC Roboteq v1.7 02/01/05 s Entering RS232 from R/C or Analog modeData Logging String in R/C or Analog mode Establishing Manual Communication with a PC RS232 Mode if default RS232 Commands SetSet Motor Command Value A3F Set Accessory OutputsQuery Power Applied to Motors RS232 Commands Set B7F Query Analog Inputs Query Amps Consumed by Motors Query Digital Inputs Query Heatsink TemperaturesQuery Battery Voltages RS232 Commands Set Read parameter Read and Modify Controller SettingsModify parameter Apply Parameter Changes Optical Encoder CommandsCommands Acknowledge and Error Messages Reset Controller Watchdog time-out Command AcknowledgementCommand Error RS-232 Watchdog RS232 Accessible Parameter Table RS232 Accessible Parameter Table PID Automatic Switching from RS232 to RC Mode Automatic Switching from RS232 to RC Mode Analog and R/C Modes Data Logging String Format Data Logging Cables Data Logging Cables Dec Hex Decimal to Hexadecimal Conversion Table Decimal to Hexadecimal Conversion Table 106 Analog Control and Operation Analog Control and Operation Connector I/O Pin Assignment Analog ModeUnused Connecting a Potentiometer Connecting to a Voltage SourceConnecting to a Voltage Source = U/R = 5V / 1000 Ohms = 0.005A = 5mA Selecting the Potentiometer Value Analog Deadband Adjustment Analog Deadband Adjustment Under Voltage Safety Power-On SafetyData Logging in Analog Mode Modified Analog cable with RS232 output data logging for PC Data Logging in Analog Mode 114 Selecting the Position Mode Closed Loop Position Mode Position Sensor Selection Closed Loop Position ModeSensor Mounting Sensor and Motor Polarity Potentiometer wiringUsing Optical Encoders in Position Mode Potentiometer wiring Important Safety Warning Safety limit switches interrupting power to motors Adding Safety Limit Switches Control Loop Description Using Current Limiting as Protection Control Loop Description PID tuning in Position Mode Selecting the Speed Mode Closed Loop Speed Mode Tachometer or Encoder Mounting Using Optical Encoder for Speed Feedback AX2850 onlyTachometer wiring Closed Loop Speed Mode Speed Sensor and Motor Polarity Speed Sensor and Motor Polarity Adjust Offset and Max Speed AX2500/2850 Motor Controller User’s Manual 127 PID algorithm used in Speed mode PID tuning in Speed Mode PID tuning in Speed Mode 130 Optical Incremental Encoders Overview Installing Connecting Using Encoder ModuleOptical Incremental Encoders Overview Recommended Encoder Types Installing, Connecting and Using the Encoder Mod Installing the Encoder Module Installing the Encoder ModulePulse Frequency in Hz = RPM / 60 * PPR Position of Encoder Module on Controller’s main board Connecting the Encoder Connecting the EncoderPin Name Cable Color Motor Encoder Polarity Matching Voltage Levels, Thresholds and Limit Switches Wiring Optional Limit Switches Wiring Optional Limit Switches Using the Encoder Module to Measure Distance Using the Encoder to Measure Speed Using the Encoder to Measure Speed Distance = Destination Counter value / Divider Using the Encoder to Track Position RS232 Communication with the Encoder Module ?Q0 RS232 Encoder Command SetRead Encoder Counter ?q or Q n Or !Q n Set/Reset Encoder Counters and Destination RegistersRS232 Encoder Command Set Read Speed Read Distance Read Encoder Limit Switch StatusRead Speed/Distance Read / Modify Encoder Module Registers and Parameters Switch Value?w or ?W Controller replies, value is Address Parameter Description Size Access Encoder Hardware ID code Register Description Counter 1 Switch StatusSpeed or Distance 1 or Counter Read/Write Mailbox Encoder Threshold Counter Read Data FormatSpeed 1 Time Base 1 FFFFFF15 Encoder Testing and Setting Using the PC Utility Encoder Testing and Setting Using the PC Utility Encoder Module Parameters Setting Exercising the Motors Updating the Encoder SoftwareViewing Encoder Data Programming using built-in Switches and Display Configuring Controller using SwitchesProgramming Methods Configuring the Controller using the Switches Entering Programming Mode Changing parameters Restoring factory defaultsSpecial Case of Joystick Calibration Programmable Parameters List Exiting the Parameter Setting Mode Programmable Parameters List Order Letter Description Possible Values default Pages 158 Downloading and Installing the Utility Using the Roborun Configuration UtilitySystem Requirements Using the Roborun Configuration Utility Connecting the Controller to the PC Roborun Frame, Tab and Menu Descriptions Roborun Frame, Tab and Menu Descriptions Loading, Changing Controller Parameters Parameter Selection and Setting, and Special FunctionsFile and Program Management Commands Getting On-Screen Help Controls Settings Effect of Digital Inputs Power SettingsLeft/Right Adjust Acceleration Setting Deadband Analog or R/C Specific SettingsJoystick Timing Closed Loop Parameters Viewing the Parameters Summary Running the Motors Optical Encoder OperationOptical Encoder Operation Run/Stop Button Motor Power settingMeasurement Transmit and Receive Data Real-Time Strip Chart RecorderInput Status and Output Setting Running the Motors Logging Data to Disk Parameter Header Data type/range Measured Parameter Connecting a Joystick Viewing and Logging Data in Analog and R/C Modes Operating the AX2500/2850 over a Wired or Wireless LANLoading and Saving Profiles to Disk Roboserver screenshot when idle Operating the AX2500/2850 over a Wired or Wireless LAN Creating Customized Object Files Updating the Controller’s Software Creating Customized Object Files Objectmaker creates controller firmware with custom defaults 176 Mechanical Dimensions Mechanical SpecificationsMechanical Dimensions Mounting Considerations Mechanical SpecificationsThermal Considerations Wire Gauge Outside Diameter Color Length Wire DimensionsWeight Wire Dimensions 180