How to gradually increase targetAngularVelocity value of a Configurable joint?

How do I gradually increase the speed of a configurable joint? When I assigned a value of Vector3(0,0,5) to a conjo rotating about z-axis, value 5 is applied instantly. Is there a way to make the speed goes up gradually to assigned speed?

You can use Vector3.Lerp(). As an example:

private const float Duration = 2f;
private float endTime = -1f;
private Vector3 startValue;
private Vector3 endValue;

public void Update() {

    if (Time.time<=endTime) {
        float a = (endTime-Time.time)/Duration;
        Debug.Log(Vector3.Lerp(startValue,endValue,a));
    }
    else if (Input.GetKeyDown(KeyCode.E)) {
        endTime = Time.time + Duration;
        startValue = transform.position;
        endValue = startValue + Vector3.right;
    }
}