add conversion

src/device/xm.rs

@@ -1,11 +1,8 @@
-//! MX robotis register (protocol v1)
+//! XM robotis register (protocol v1)
 //!
-//! Despite some minor differences among MX variants, it should work for
-//! * MX-28
-//! * MX-64
-//! * MX-106
+//! Tested for the XM430-W210 flashed in protocol v1
 //!
-//! See <https://emanual.robotis.com/docs/en/dxl/mx/mx-28/> for example.
+//! See <https://emanual.robotis.com/docs/en/dxl/x/xm430-w210> for example.
 
 use crate::device::*;
 
@@ -25,7 +22,9 @@ reg_read_write!(max_voltage_limit, 32, u16);
 reg_read_write!(min_voltage_limit, 34, u16);
 reg_read_write!(acceleration_limit, 40, u32);
 reg_read_write!(current_limit, 38, u16);
+reg_read_write!(torque_limit, 38, u16); //Duplicate with MX name for compatibility
 reg_read_write!(velocity_limit, 44, u32);
+reg_read_write!(moving_speed, 44, u32); //Duplicate with MX name for compatibility
 reg_read_write!(max_position_limit, 48, u32);
 reg_read_write!(min_position_limit, 52, u32);
 
@@ -61,3 +60,99 @@ reg_read_only!(velocity_trajectory, 136, u32);
 reg_read_only!(position_trajectory, 140, u32);
 reg_read_only!(present_input_voltage, 144, u16);
 reg_read_only!(present_temperature, 146, u8);
+
+
+
+/// Unit conversion for XM motors
+pub mod conv {
+    use std::f64::consts::PI;
+
+    /// Dynamixel angular position to radians
+    ///
+    /// Works in joint and multi-turn mode
+    pub fn dxl_pos_to_radians(pos: i32) -> f64 {
+        (2.0 * PI * (pos as f64) / 4096.0) - PI
+    }
+    /// Radians to dynamixel angular position
+    ///
+    /// Works in joint and multi-turn mode
+    pub fn radians_to_dxl_pos(rads: f64) -> i32 {
+        (4096.0 * (PI + rads) / (2.0 * PI)) as i16
+    }
+
+    /// Dynamixel absolute speed to radians per second
+    ///
+    /// Works for moving_speed in joint mode for instance
+    pub fn dxl_abs_speed_to_rad_per_sec(speed: u32) -> f64 {
+        let rpm = speed as f64 * 0.229;
+        rpm * 0.10472
+    }
+    /// Radians per second to dynamixel absolute speed
+    ///
+    /// Works for moving_speed in joint mode for instance
+    pub fn rad_per_sec_to_dxl_abs_speed(speed: f64) -> u32 {
+        let rpm = speed / 0.10472;
+        (rpm / 0.229) as u16
+    }
+    /// Dynamixel speed to radians per second
+    ///
+    /// Works for present_speed for instance
+    pub fn dxl_oriented_speed_to_rad_per_sec(speed: u32) -> f64 {
+        let cw = (speed >> 11) == 1;
+
+        let rad_per_sec = dxl_abs_speed_to_rad_per_sec(speed % 1024);
+
+        match cw {
+            true => rad_per_sec,
+            false => -rad_per_sec,
+        }
+    }
+    /// Radians per second to dynamixel speed
+    ///
+    /// Works for present_speed for instance
+    pub fn rad_per_sec_to_dxl_oriented_speed(speed: f64) -> u32 {
+        let raw = rad_per_sec_to_dxl_abs_speed(speed.abs());
+
+        match speed < 0.0 {
+            true => raw,
+            false => raw + 2048,
+        }
+    }
+
+    /// Dynamixel absolute load to torque percentage
+    ///
+    /// Works for torque_limit for instance
+    pub fn dxl_load_to_abs_torque(load: u16) -> f64 {
+        load as f64 / 1193.0 * 100.0
+    }
+    /// Torque percentage to dynamixel absolute load
+    ///
+    /// Works for torque_limit for instance
+    pub fn torque_to_dxl_abs_load(torque: f64) -> u16 {
+        assert!((0.0..=100.0).contains(&torque));
+
+        (torque * 1193.0 / 100.0) as u16
+    }
+    /// Dynamixel load to torque percentage
+    ///
+    /// Works for present_torque for instance
+    pub fn dxl_load_to_oriented_torque(load: u16) -> f64 {
+        let cw = (load >> 10) == 1;
+
+        let torque = dxl_load_to_abs_torque(load % 1193);
+
+        match cw {
+            true => torque,
+            false => -torque,
+        }
+    }
+    /// Torque percentage to dynamixel load
+    pub fn oriented_torque_to_dxl_load(torque: f64) -> u16 {
+        let load = torque_to_dxl_abs_load(torque.abs());
+
+        match torque < 0.0 {
+            true => load,
+            false => load + 1193,
+        }
+    }
+}