DDPG Actor output saturate

[m5823779]

Hello~ I have some question about DDPG
Ｗhen my action dimension = 1, the result is good, but when my action dimension = 2 (the activation function is tanh and sigmoid), the output of actor will saturate.
Here is the result what I said: https://github.com/m5823779/DDPG
By the way, I use batch normalization only in my actor network.
Do you know where is the problem?