Speed profile and types of motor motion

Speed profile

Overview

Prior to motor operation, the acceleration, deceleration, and maximum speed values of the motion must be set in advance. It depends on the following;

• Motor Specifications
• Power supply voltage
• load (e.g. on a load cell)
• Voltage control or current control You need to set the values as you check them in the real environment.

Values to be set

Acceleration(acc), Deceleration(dec), and maxSpeed. You can also set the minimum speed (minSpeed) as a function of the motor driver, but it is fixed at 0 on the firmware side because it is unlikely to be used in the field.

Type of motor operation

Constant speed driving

This command reaches the speed specified by the acceleration/deceleration rate of the pre-set speed profile and then maintains a constant speed. It continues to rotate until 0 is specified or a stop command is sent. The range of speed that can be specified is limited to the maximum speed of the speed profile. It will be BUSY state during acceleration and deceleration.

Positional driving

The trapezoidal drive to the specified position is performed according to the speed profile. In other words, it accelerates according to the acceleration of the speed profile, drives at a constant speed when it reaches the maximum speed, and then decelerates at a specified deceleration rate. The motor starts deceleration at the timing calculated backwards to stop at a specified position. It remains in the BUSY state until the motor stops.

Servo mode

This is not a function of the motor driver, but a type of driving implemented in the firmware. It constantly updates the speed of constant speed operation to follow a given target position. This is a method of operation similar to a radio controlled servo motor. No other motor movement commands can be sent while the motor is operating in this mode.

Types of stops

There are two options with a total of four different commands, as follows;

• Decelerate according to the speed profile or stop instantly.
• Keep magnetized or put in a high impedance(High Z) state after stopping.

State after stop	Deceleration stop	Momentary stop
Excitation	SoftStop	HardStop
HiZ	SoftHiZ	HardHiZ

The excited state is the state in which the torque to hold the position of the motor is applied by the voltage according to KVAL_HOLD or the current according to the value of TVAL_HOLD. The high impedance state is the state where the current is cut off and there is no holding torque.