Handling of TACHOMETER value overflow

[TakaakiNumai]

Abstract

The TACHOMETER value is converted to double, which results in an incorrect value during overflow.

vesc/vesc_driver/src/vesc_packet.cpp

Lines 276 to 283 in 3d25c6a

 /** 
  * @brief Gets the current position 
  * @return The current position 
  **/ 
 double VescPacketValues::getPosition() const 
 { 
   return readBuffer(TACHOMETER, 4); 
 } 

How to Reproduce the Bug

If the motor continues to rotate until TACHOMETER overflows, the return value of getPosition jumps

Suggestion

Calculate the difference from the previous value and cast the value to double.
The difference shall not exceed the maximum value of int.

int tachometer = (int)readBuffer(TACHOMETER, 4);
static int tachometer_last = tachometer ;
current_pose += (double)(tachometer - tachometer_last);
tachometer_last = tachometer;