优化了平衡，尤其对于向后倾倒的几种极限情况进行优化

Shibo-main-TOMMY/lib/SCServo/examples/SCSCL/Ping/Ping.ino

@@ -0,0 +1,40 @@
+/*
+Ping() to test a servo on the bus is ready.
+*/
+
+// the uart used to control servos.
+// GPIO 18 - S_RXD, GPIO 19 - S_TXD, as default.
+#define S_RXD 18
+#define S_TXD 19
+
+#include <SCServo.h>
+
+SCSCL sc;
+
+int TEST_ID = 3;
+
+int LEDpin = 13;
+void setup()
+{
+  pinMode(LEDpin,OUTPUT);
+  digitalWrite(LEDpin, HIGH);
+  Serial.begin(115200);
+  Serial1.begin(1000000, SERIAL_8N1, S_RXD, S_TXD);
+  sc.pSerial = &Serial1;
+  delay(1000);
+}
+
+void loop()
+{
+  int ID = sc.Ping(TEST_ID);
+  if(ID!=-1){
+    digitalWrite(LEDpin, LOW);
+    Serial.print("Servo ID:");
+    Serial.println(ID, DEC);
+    delay(100);
+  }else{
+    Serial.println("Ping servo ID error!");
+    digitalWrite(LEDpin, HIGH);
+    delay(2000);
+  }
+}