i need help with 2 questions 3 and 4 NOT 5. Robotics subject
3. Reinforcement Learning
Reinforcements learning (RL) agents learn by taking state-dependent actions and experiencing reward arising from interaction with their environments. One method is to use a table-based Q-learning algorithm.
Figure 1: The inverted pendulum problem
Q-learning tables are discrete, but most real-world tasks involve systems that have continuous states and are controlled using continuous actions. With this in mind, consider how a table-based Q-learning algorithm could learn to balance an inverted pendulum (as shown in Fig. 1). To achieve this:
(a) Describe a suitable reward function.
[3 marks]
(b) Describe a suitable choice of states and explain why they are appropriate.
[3 marks]
(c) Describe a suitable choice of actions and explain why they are appropriate and how they relate to the states discussed in part (a).
[3 marks]
(d) Discuss how an inverted pendulum task could be either an MDP or a POMDP. [2 marks]
Question 3 continued …
Question 3 continued
(e) Discuss how simulated experience generated from a model within a RL agent can increase the speed with which the RL algorithm convergence. How can this assist finding a solution in the inverted pendulum task?
[4 marks]
(f) Dyna-Q algorithm is one such model-based approach to RL. Using high-level pseudo code in no more than 12 lines, describe the operation of the Dyna-Q algorithm and describe all its key terms.
[5 marks]
4. State estimation
(a) When building a full state feedback controller, why is if often necessary to use some form of state estimator?
[3 marks]
(b) The Luenberger observer is a deterministic state estimator. Draw its signal flow graph to illustrate its operation and explain the design and function of the Luenberger gain L.
[3 marks]
(c) The Kalman filter is a stochastic state estimator. Draw and compare a signal flow graph of the Kalman estimator with that of the Luenberger observer, illustrating all the Kalman estimator’s important components, including its noise sources.
[4 marks]
Question 4 continued …
Question 4 continued
(d) The Kalman filter iteratively computes 5 variables as illustrated below
Write a short paragraph on each of the terms 1 – 5 to explain their meaning and function.
[10 marks]
5. Gaussian processes
Describe the main difference between using Gaussian Processes and Support Vector Machines in approximating linear functions.
[20 marks]
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