Sticky brake

Feature: Implement sticky brake > Sticky brake will use strong, phase-shorting brake at standstill and untill a certain ERPM is crossed (brake is disarmed). After that, regular braking current will be used until the strong brake is armed again by crossing the arm threshold (arm and disarm thresholds are potential new configuration values).
lukash · Sep 5, 2024 · 5fa87b6 · 5fa87b6
1 parent 25f6320
commit 5fa87b6
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Showing 5 changed files with 65 additions and 12 deletions.
diff --git a/src/conf/datatypes.h b/src/conf/datatypes.h
@@ -205,6 +205,8 @@ typedef struct {
     bool startup_pushstart_enabled;
     bool startup_dirtylandings_enabled;
     float brake_current;
+    uint16_t brake_arm_threshold;
+    uint16_t brake_disarm_threshold;
     float ki_limit;
     float booster_angle;
     float booster_ramp;

diff --git a/src/conf/settings.xml b/src/conf/settings.xml
@@ -1309,6 +1309,46 @@ p, li { white-space: pre-wrap; }
             <suffix> A</suffix>
             <vTx>7</vTx>
         </brake_current>
+        <brake_arm_threshold>
+            <longName>Brake Arm Threshold</longName>
+            <type>2</type>
+            <transmittable>1</transmittable>
+            <description>&lt;!DOCTYPE HTML PUBLIC &quot;-//W3C//DTD HTML 4.0//EN&quot; &quot;http://www.w3.org/TR/REC-html40/strict.dtd&quot;&gt;
+&lt;html&gt;&lt;head&gt;&lt;meta name=&quot;qrichtext&quot; content=&quot;1&quot; /&gt;&lt;style type=&quot;text/css&quot;&gt;
+p, li { white-space: pre-wrap; }
+&lt;/style&gt;&lt;/head&gt;&lt;body style=&quot; font-family:'Roboto'; ; font-weight:400; font-style:normal;&quot;&gt;
+&lt;p style=&quot; margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px;&quot;&gt;ERPM threshold below which the brake current is armed, meaning the board will passively lock the wheel. Set to 0 to always arm if ERPM is below the Brake Disarm Threshold.&lt;/p&gt;&lt;/body&gt;&lt;/html&gt;</description>
+            <cDefine>CFG_DFLT_BRAKE_ARM_THRESHOLD</cDefine>
+            <editorScale>1</editorScale>
+            <editAsPercentage>0</editAsPercentage>
+            <maxInt>2000</maxInt>
+            <minInt>0</minInt>
+            <showDisplay>0</showDisplay>
+            <stepInt>20</stepInt>
+            <valInt>50</valInt>
+            <suffix> ERPM</suffix>
+            <vTx>3</vTx>
+        </brake_arm_threshold>
+        <brake_disarm_threshold>
+            <longName>Brake Disarm Threshold</longName>
+            <type>2</type>
+            <transmittable>1</transmittable>
+            <description>&lt;!DOCTYPE HTML PUBLIC &quot;-//W3C//DTD HTML 4.0//EN&quot; &quot;http://www.w3.org/TR/REC-html40/strict.dtd&quot;&gt;
+&lt;html&gt;&lt;head&gt;&lt;meta name=&quot;qrichtext&quot; content=&quot;1&quot; /&gt;&lt;style type=&quot;text/css&quot;&gt;
+p, li { white-space: pre-wrap; }
+&lt;/style&gt;&lt;/head&gt;&lt;body style=&quot; font-family:'Roboto'; ; font-weight:400; font-style:normal;&quot;&gt;
+&lt;p style=&quot; margin-top:0px; margin-bottom:0px; margin-left:0px; margin-right:0px; -qt-block-indent:0; text-indent:0px;&quot;&gt;ERPM threshold above which the board will not passively lock the wheel and apply the braking current instead.&lt;/p&gt;&lt;/body&gt;&lt;/html&gt;</description>
+            <cDefine>CFG_DFLT_BRAKE_DISARM_THRESHOLD</cDefine>
+            <editorScale>1</editorScale>
+            <editAsPercentage>0</editAsPercentage>
+            <maxInt>2000</maxInt>
+            <minInt>0</minInt>
+            <showDisplay>0</showDisplay>
+            <stepInt>100</stepInt>
+            <valInt>500</valInt>
+            <suffix> ERPM</suffix>
+            <vTx>3</vTx>
+        </brake_disarm_threshold>
         <ki_limit>
             <longName>I Term Limit</longName>
             <type>1</type>
@@ -3475,6 +3515,8 @@ p, li { white-space: pre-wrap; }
         <ser>startup_pushstart_enabled</ser>
         <ser>startup_dirtylandings_enabled</ser>
         <ser>brake_current</ser>
+        <ser>brake_arm_threshold</ser>
+        <ser>brake_disarm_threshold</ser>
         <ser>ki_limit</ser>
         <ser>booster_angle</ser>
         <ser>booster_ramp</ser>
@@ -3656,6 +3698,8 @@ p, li { white-space: pre-wrap; }
                     <param>startup_dirtylandings_enabled</param>
                     <param>::sep::Holding</param>
                     <param>brake_current</param>
+                    <param>brake_arm_threshold</param>
+                    <param>brake_disarm_threshold</param>
                 </subgroupParams>
             </subgroup>
             <subgroup>

diff --git a/src/main.c b/src/main.c
@@ -87,6 +87,8 @@ typedef struct {
     int beep_reason;
     bool beeper_enabled;
 
+    bool braking;
+
     Leds leds;
 
     // Lights Control Module - external lights control
@@ -1042,7 +1044,7 @@ static void apply_turntilt(data *d) {
 static void brake(data *d) {
     // Brake timeout logic
     float brake_timeout_length = 1;  // Brake Timeout hard-coded to 1s
-    if (d->motor.abs_erpm > ERPM_MOVING_THRESHOLD || d->brake_timeout == 0) {
+    if (d->motor.erpm_smooth > ERPM_MOVING_THRESHOLD || d->brake_timeout == 0) {
         d->brake_timeout = d->current_time + brake_timeout_length;
     }
 
@@ -1052,21 +1054,23 @@ static void brake(data *d) {
 
     VESC_IF->timeout_reset();
 
-    // If brake current is set to 0 don't do anything
-    if (d->float_conf.brake_current == 0) {
-        return;
+    if (d->motor.erpm_smooth > d->float_conf.brake_disarm_threshold) {
+        d->braking = false;
+    } else if (d->motor.erpm_smooth < d->float_conf.brake_arm_threshold ||
+               d->float_conf.brake_arm_threshold == 0) {
+        d->braking = true;
     }
 
-    // Use brake current over certain ERPM to prevent the board skidding to a stop when deactivated
-    // at speed?
-    if (d->motor.abs_erpm > 2000) {
+    if (d->braking) {
+        // Use DC control mode as it has better holding power
+        // Also improves with 6.05 shorting feature
+        VESC_IF->mc_set_duty(0);
+        d->braking = true;
+    } else {
+        // Use brake current over certain ERPM to prevent the board
+        // skidding to a stop when deactivated at speed
         VESC_IF->mc_set_brake_current(d->float_conf.brake_current);
-        return;
     }
-
-    // Use DC control mode as it has better holding power
-    // Also improves with 6.05 shorting feature
-    VESC_IF->mc_set_duty(0);
 }
 
 static void set_current(data *d, float current) {

diff --git a/src/motor_data.c b/src/motor_data.c
@@ -25,6 +25,7 @@
 
 void motor_data_reset(MotorData *m) {
     m->duty_smooth = 0;
+    m->erpm_smooth = 0;
 
     m->acceleration = 0;
     m->accel_idx = 0;
@@ -47,6 +48,7 @@ void motor_data_configure(MotorData *m, float frequency) {
 void motor_data_update(MotorData *m) {
     m->erpm = VESC_IF->mc_get_rpm();
     m->abs_erpm = fabsf(m->erpm);
+    m->erpm_smooth = m->erpm_smooth * 0.9 + m->abs_erpm * 0.1;
     m->erpm_sign = sign(m->erpm);
 
     m->current = VESC_IF->mc_get_tot_current_directional_filtered();

diff --git a/src/motor_data.h b/src/motor_data.h
@@ -28,6 +28,7 @@ typedef struct {
     float erpm;
     float abs_erpm;
     float last_erpm;
+    float erpm_smooth;
     int8_t erpm_sign;
 
     float current;