Linear actuators

Table of contents

  1. Important notes
  2. Basic specs
  3. General message format
    1. Byte 1
  4. Commands
    1. 0x0F: Position command
      1. Desired position (DPOS)
      2. Delay in motor enable
    2. 0xF5_0x00: Configure baud rate
      1. Example
    3. 0xF5_0x01: Configure PWM frequency
      1. PWM_MAX
      2. Example
  5. Replies

Important notes

  • ⚠ If the actuator does not receive a command within 1 second, if will turn off the clutch and enter safe mode. Suggested refresh rate is 100 ms.
  • The datasheet notes that for proper care, the clutch should be enabled at least 20ms before the motor is enabled, and the motor should be disabled at least 20ms before disabling the clutch.

Basic specs

Item Value
Input voltage 10-30VDC
Max current 5.8A
Operating temperature -40$\degree$C to 85$\degree$C
Actuator working distance 3.1 inches
CAN baud rate 250K (default) or 500K

General message format

Uses 29-bit “extended” CAN2.0b IDs.

Messages are 8 bytes.

Byte Description
0 Message data type
1 Flags, confirmation requests, and data type extras
2-7 Message data

Byte 1

Bit Description
7 Confirmation flag. 1 = Actuator will echo the message back.
6 Auto reply flag. 1 = Actuator will reply that it is set up for that message. Does not respond to all messages, only supported ones.
0-5 Data type

Commands

0x0F: Position command

Byte.Bit Description/value
0 15 (0x0f) Datatype
1 See above. Bits 0-5 must be 0x0A.
2 DPOS_LOW: Least significant byte of DPOS. See below.
3.7 Clutch enable. See note below.
3.6 Motor enable.
3.5 DPOS_HI. The most significant 5 bits of the DPOS value.
4-7 0 (0x00). Not used.

Desired position (DPOS)

This is a 13-bit value, the concatenation of DPOS_HI+DPOS_LOW.

The actual position of the LA is $pos=0.001x+0.5$ inches, where $x$ is DPOS_LOW.

Example: DPOS_HI = 1 0100, DPOS_LOW=1000 0100. Then DPOS=1 0100 1000 0100, or 5252 in decimal. Then $pos=0.001\times 5252+0.5=5.752$ inches.

Delay in motor enable

The datasheet notes that for proper care, the clutch should be enabled at least 20ms before the motor is enabled, and the motor should be disabled at least 20ms before disabling the clutch.

0xF5_0x00: Configure baud rate

The baud rate can be set to either 250K (default) or 500K. The specified value is persisted across boots.

Byte Description/value
0 0xF5
1 See above. Bits 0-5 must be 0x00.
2 0x00
3 0x00
4 0x00=250K. 0x01=500K.
5-7 0 (0x00). Not used.

Example

0xF5 0x00 0x00 0x00 0x01 0x00 0x00 0x00

Sets baud rate to 500K.

0xF5_0x01: Configure PWM frequency

Byte Description/value
0 0xF5
1 See above. Bits 0-5 must be 0x01.
2 0x00
3 0x02
4 MIN_PWM, from 0-100%.
5 MAX_PWM, from 0-100%.
6-7 PWM_FREQ, with byte 6 being LSB.

These values determine how much force the LA will use.

PWM_MAX

Set PWM_MAX to be as low as possible while still giving the LA enough force to press the pedal.

Example

0xF5 0x01 0 0x02 0x0A 0x5A 0x90 0x01

This sets MIN PWM to 10% (0x0A) and MAX PWM to 90 (0x5A), and PWM FREQUENCY to 400Hz (0x0190).

Many commands were omitted. See datasheet for all messages.

Replies

Not yet noted. See datasheet for reply information.