Improve armar7 platform movement

source/RobotAPI/components/units/RobotUnit/NJointControllers/NJointHolonomicPlatformVelocityControllerWithRamp.cpp

@@ -39,9 +39,11 @@ namespace armarx
             << "The actuator " << cfg->platformName << " has no control mode "
             << ControlModes::HolonomicPlatformVelocity;
 
-        velocitySensor =
-            useSensorValue(cfg->platformName + "asdf")->asA<SensorValueHolonomicPlatformVelocity>();
-        ARMARX_CHECK_EXPRESSION(velocitySensor) << "No sensor value for " << cfg->platformName;
+        const auto sensor = useSensorValue(cfg->platformName);
+        ARMARX_CHECK_EXPRESSION(sensor) << "No sensor value for " << cfg->platformName;
+        velocitySensor = sensor->asA<SensorValueHolonomicPlatformVelocity>();
+        ARMARX_CHECK_EXPRESSION(velocitySensor)
+            << "Sensor value for " << cfg->platformName << " has invalid type";
 
         ramp.setMaxPositionAcceleration(cfg->maxPositionAcceleration);
         ramp.setMaxOrientationAcceleration(cfg->maxOrientationAcceleration);