refactor(balance): remove balance-bot safety cutoffs, front VESC drive only

Robot is no longer a balance bot. Remove:
- TILT_CUTOFF_DEG (±25° tilt cutoff) from config.h
- BAL_TILT_FAULT enum value from orin_serial.h
- CMD_PID / orin_pid_t (balance PID tuning) from protocol
- Steer differential (RPM_PER_STEER_UNIT) from drive task
- VESC_ID_B drive command — front VESC (ID 61) only

Update VESC CAN IDs: 56→61 (front), 68→79 (rear).
VESC_ID_B retained for rear telemetry RX only.
ESTOP and heartbeat watchdog unchanged.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

esp32s3/balance/main/config.h

@@ -24,9 +24,9 @@
 #define VESC_CAN_RX_GPIO        1       /* SN65HVD230 RXD → ESP32 TWAI RX */
 #define VESC_CAN_RX_QUEUE       32
 
-/* VESC node IDs — matched to bd-wim1 TELEM_VESC_LEFT/RIGHT mapping */
+/* VESC node IDs */
-#define VESC_ID_A               56u     /* TELEM_VESC_LEFT  (0x81) */
+#define VESC_ID_A               61u     /* FRONT VESC — drive + telemetry (0x81) */
-#define VESC_ID_B               68u     /* TELEM_VESC_RIGHT (0x82) */
+#define VESC_ID_B               79u     /* REAR  VESC — telemetry only    (0x82) */
 
 /* ── Safety / timing ── */
 #define HB_TIMEOUT_MS           500u    /* heartbeat watchdog: disarm if exceeded */
@@ -36,7 +36,3 @@
 
 /* ── Drive → VESC RPM scaling ── */
 #define RPM_PER_SPEED_UNIT      5       /* speed_units=1000 → 5000 ERPM */
-#define RPM_PER_STEER_UNIT      3       /* steer differential scale */
-
-/* ── Tilt cutoff ── */
-#define TILT_CUTOFF_DEG         25.0f

esp32s3/balance/main/main.c

@@ -63,20 +63,14 @@ static void drive_task(void *arg)
         bool hb_timeout   = (now_ms - g_orin_ctrl.hb_last_ms) > HB_TIMEOUT_MS;
         bool drive_stale  = (now_ms - g_orin_drive.updated_ms) > DRIVE_TIMEOUT_MS;
 
-        int32_t left_erpm  = 0;
+        int32_t front_erpm = 0;
-        int32_t right_erpm = 0;
 
         if (g_orin_ctrl.armed && !g_orin_ctrl.estop &&
             !hb_timeout && !drive_stale) {
-            int32_t spd = (int32_t)g_orin_drive.speed * RPM_PER_SPEED_UNIT;
+            front_erpm = (int32_t)g_orin_drive.speed * RPM_PER_SPEED_UNIT;
-            int32_t str = (int32_t)g_orin_drive.steer * RPM_PER_STEER_UNIT;
-            left_erpm  = spd + str;
-            right_erpm = spd - str;
         }
 
-        /* VESC_ID_A (56) = LEFT, VESC_ID_B (68) = RIGHT per bd-wim1 protocol */
+        vesc_can_send_rpm(VESC_ID_A, front_erpm);
-        vesc_can_send_rpm(VESC_ID_A, left_erpm);
-        vesc_can_send_rpm(VESC_ID_B, right_erpm);
     }
 }
 

esp32s3/balance/main/orin_serial.c

@@ -17,9 +17,8 @@
 static const char *TAG = "orin";
 
 /* ── Shared state ── */
-orin_drive_t   g_orin_drive   = {0};
+orin_drive_t   g_orin_drive = {0};
-orin_pid_t     g_orin_pid     = {0};
+orin_control_t g_orin_ctrl  = {.armed = false, .estop = false, .hb_last_ms = 0};
-orin_control_t g_orin_ctrl    = {.armed = false, .estop = false, .hb_last_ms = 0};
 
 /* ── CRC8-SMBUS (poly=0x07, init=0x00) ── */
 static uint8_t crc8(const uint8_t *data, uint8_t len)
@@ -188,25 +187,6 @@ static void dispatch_cmd(uint8_t type, const uint8_t *payload, uint8_t len,
         orin_send_ack(tx_q, type);
         break;
 
-    case CMD_PID:
-        if (len < 12u) { orin_send_nack(tx_q, type, ERR_BAD_LEN); break; }
-        /* float32 big-endian: copy and swap bytes */
-        {
-            uint32_t raw;
-            raw = ((uint32_t)payload[0] << 24u) | ((uint32_t)payload[1] << 16u) |
-                  ((uint32_t)payload[2] <<  8u) |  (uint32_t)payload[3];
-            memcpy((void*)&g_orin_pid.kp, &raw, 4u);
-            raw = ((uint32_t)payload[4] << 24u) | ((uint32_t)payload[5] << 16u) |
-                  ((uint32_t)payload[6] <<  8u) |  (uint32_t)payload[7];
-            memcpy((void*)&g_orin_pid.ki, &raw, 4u);
-            raw = ((uint32_t)payload[8] << 24u) | ((uint32_t)payload[9] << 16u) |
-                  ((uint32_t)payload[10] << 8u) |  (uint32_t)payload[11];
-            memcpy((void*)&g_orin_pid.kd, &raw, 4u);
-            g_orin_pid.updated = true;
-        }
-        orin_send_ack(tx_q, type);
-        break;
-
     case CMD_OTA_CHECK:
         /* Trigger an immediate Gitea version check */
         gitea_ota_check_now();

esp32s3/balance/main/orin_serial.h

@@ -23,12 +23,11 @@
 #define CMD_DRIVE           0x02u   /* int16 speed + int16 steer, BE */
 #define CMD_ESTOP           0x03u   /* uint8: 1=assert, 0=clear */
 #define CMD_ARM             0x04u   /* uint8: 1=arm, 0=disarm */
-#define CMD_PID             0x05u   /* float32 kp, ki, kd, BE */
 
 /* ── Telemetry types: ESP32 → Orin ── */
 #define TELEM_STATUS        0x80u   /* status @ 10 Hz */
-#define TELEM_VESC_LEFT     0x81u   /* VESC ID 56 telemetry @ 10 Hz */
+#define TELEM_VESC_LEFT     0x81u   /* VESC ID 61 (front) telemetry @ 10 Hz */
-#define TELEM_VESC_RIGHT    0x82u   /* VESC ID 68 telemetry @ 10 Hz */
+#define TELEM_VESC_RIGHT    0x82u   /* VESC ID 79 (rear)  telemetry @ 10 Hz */
 #define TELEM_OTA_STATUS    0x83u   /* OTA state + progress (bd-1s1s) */
 #define TELEM_VERSION_INFO  0x84u   /* firmware version report (bd-1s1s) */
 #define RESP_ACK            0xA0u
@@ -51,12 +50,11 @@
 #define ERR_OTA_BUSY        0x05u
 #define ERR_OTA_NO_UPDATE   0x06u
 
-/* ── Balance state (mirrored from TELEM_STATUS.balance_state) ── */
+/* ── Drive state (mirrored from TELEM_STATUS.balance_state) ── */
 typedef enum {
-    BAL_DISARMED   = 0,
+    BAL_DISARMED = 0,
-    BAL_ARMED      = 1,
+    BAL_ARMED    = 1,
-    BAL_TILT_FAULT = 2,
+    BAL_ESTOP    = 3,
-    BAL_ESTOP      = 3,
 } bal_state_t;
 
 /* ── Shared state written by RX task, consumed by main/vesc tasks ── */
@@ -66,11 +64,6 @@ typedef struct {
     volatile uint32_t updated_ms;   /* esp_timer tick at last CMD_DRIVE */
 } orin_drive_t;
 
-typedef struct {
-    volatile float    kp, ki, kd;
-    volatile bool     updated;
-} orin_pid_t;
-
 typedef struct {
     volatile bool     armed;
     volatile bool     estop;
@@ -86,7 +79,6 @@ typedef struct {
 
 /* ── Globals (defined in orin_serial.c, extern here) ── */
 extern orin_drive_t   g_orin_drive;
-extern orin_pid_t     g_orin_pid;
 extern orin_control_t g_orin_ctrl;
 
 /* ── API ── */