飞行模拟控制器油门加速/减速逻辑实现技术咨询

需求说明 #

• 油门无怠速状态，仅包含0（关闭）和最大速度两种状态切换逻辑
• 油门输入值范围为-1至1：
  • 当输入值> -1时，速度开始提升；-1~0区间对应速度范围0~650，0~1区间对应速度范围650~1390
  • 油门值越高，加速度越大；减速过程保持恒定减速度

当前试错代码 #

void SetThrust()
{
     var revisionValue = throttle + 1;
     var outputRate = (revisionValue - 0) / (2 - 0) * 100;

     if (throttle > -1f)
     {
        //add some smooth or lerp increase * decrease speed amount
        increment = outputRate * throttleFactor;
        speedEase = (maxThrust - thrust) * speedReciprocal;
     }

     // Some logic for item2 (increase/decrease speed according to the input value))       
}


void CalulateMovement()
{
    float gravityFallByPitch = gravityAngularFactor * Mathf.Sin(transform.eulerAngles.x * Mathf.Deg2Rad);

    rotateValue = new Vector3(pitch * pitchFactor - gravityFallByPitch, yaw * yawFactor, roll * (rollFactor * Mathf.Abs(roll)));
    lerpRotate = Vector3.Lerp(lerpRotate, rotateValue, lerpFactor * Time.fixedDeltaTime);

    transform.Rotate(lerpRotate * Time.fixedDeltaTime);

    if (throttle > -1f)
    {
        if (m_rigidbody.IsSleeping())
            m_rigidbody.WakeUp();

        gravityFallByPitch = gravitySpeedFactor * Mathf.Sin(transform.eulerAngles.x * Mathf.Deg2Rad);
        thrust = (increment+gravityFallByPitch) * speedEase;
        thrust = Mathf.Clamp(thrust, minThrust, maxThrust);
        m_rigidbody.AddForce(transform.forward * thrust);
    }

    else if (throttle <= -1f && m_rigidbody.velocity.magnitude <= 1)
    {
        m_rigidbody.velocity *= 0;
        m_rigidbody.Sleep();
    }
}

问题分析 #

当前代码将加速度计算与速度缓动逻辑混合，导致加减速逻辑冲突。核心问题是没有明确区分目标速度区间和对应加速度规则，无法精准控制不同油门区间的加速度上限。

计算方法与优化思路 #

1. 明确目标速度映射 #

先将油门输入值分段映射到对应的目标速度区间：

float GetTargetSpeed(float throttle)
{
    if (throttle <= -1f)
        return 0f;
    else if (throttle <= 0f)
        // -1~0 对应 0~650：throttle+1 从0到1，线性映射
        return 650f * (throttle + 1f);
    else
        // 0~1 对应 650~1390：throttle从0到1，线性映射
        return 650f + (1390f - 650f) * throttle;
}

2. 分离加减速逻辑 #

• 加速阶段：根据油门值计算加速度，油门越高加速度越大。例如将油门值映射为加速度系数，乘以最大加速度得到当前加速度：

  // 加速度系数：-1时为0，1时为1，线性变化
  float accelFactor = Mathf.InverseLerp(-1f, 1f, throttle);
  float currentAcceleration = maxAcceleration * accelFactor;
  

• 减速阶段：当当前速度超过目标速度时，使用恒定减速度：

  float deceleration = constantDeceleration; // 自定义恒定减速度值
  

3. 基于目标速度的推力控制 #

直接根据当前速度与目标速度的差值，结合加减速规则计算推力，避免逻辑混淆：

void UpdateThrust()
{
    float targetSpeed = GetTargetSpeed(throttle);
    float currentSpeed = m_rigidbody.velocity.magnitude;
    float speedDiff = targetSpeed - currentSpeed;

    float desiredAcceleration;
    if (speedDiff > 0)
    {
        // 加速：按油门值对应加速度
        float accelFactor = Mathf.InverseLerp(-1f, 1f, throttle);
        desiredAcceleration = maxAcceleration * accelFactor;
    }
    else
    {
        // 减速：恒定减速度
        desiredAcceleration = -constantDeceleration;
    }

    // 计算所需推力（考虑重力俯仰影响）
    float gravityFallByPitch = gravitySpeedFactor * Mathf.Sin(transform.eulerAngles.x * Mathf.Deg2Rad);
    float requiredThrust = (desiredAcceleration + gravityFallByPitch) * m_rigidbody.mass;
    requiredThrust = Mathf.Clamp(requiredThrust, 0f, maxThrust);

    if (throttle > -1f)
    {
        if (m_rigidbody.IsSleeping())
            m_rigidbody.WakeUp();
        m_rigidbody.AddForce(transform.forward * requiredThrust);
    }
    else
    {
        // 油门关闭，停止并休眠刚体
        if (currentSpeed <= 1f)
        {
            m_rigidbody.velocity = Vector3.zero;
            m_rigidbody.Sleep();
        }
        else
        {
            // 未完全停止时，用恒定减速度减速
            m_rigidbody.AddForce(-transform.forward * constantDeceleration * m_rigidbody.mass);
        }
    }
}

4. 其他优化点 #

• 用Mathf.InverseLerp替代手动区间计算，代码更简洁且不易出错
• 将加减速参数（maxAcceleration、constantDeceleration）暴露为可调试的变量，方便调整手感
• 分离旋转与推力控制逻辑，保持函数职责单一
• 避免直接修改velocity，优先用AddForce实现物理驱动，保证物理系统稳定性

内容的提问来源于stack exchange，提问作者developoma