Linear actuators
Table of contents
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.