From your post it looks like Hd and Hc are plant models, and you are trying to design a PID controller that would provide stable and fast step response with zero steady-state error.
The first problem with your post is that you did not mention what sampling time you use for Hd.
The second, more serios problem, is that you are trying to use the function pidstd to do the wrong thing. This function does not design a PID controller, it simply takes a PID controller expressed as a transfer function or state-space, and converts it into a pid object. Please do
and read the documentation to better understand what this function does.
If you want to design a pid controller, you need to use the function pidtool if you want to do it interactively, or pidtune if you just want to get the pid coefficients without inetarctive tuning.
Here is the code that designs a pid controller:
>>s=tf('s'); % define Laplace transform variable
>> Hc = (-0.0042*s + 8.54) / (s + 10.86); %specify plant model
>> [controller info]=pidtune(Hc,'pid'); %design a pid controller
>>info % see crossover frequency and phase margin
>>step(feedback(controller*Hc,1)); %plot step response
Take a look at this video demo, it explains things in detail.