please help with these questions

Q-1)Consider a Hexapod robot having 6 shoulder joints and 6 elbow joints. Each joint uses 1 DC motor for actuation. How many digital control pins of a microcontroller are required to control the robot most effectively?
Q-2)If the total load on the robot mentioned in (Question: 1) is 3 Kg and length of both shoulder arm and elbow arm is 5 cm. What is the minimum torque requirement of the elbow motor to make the robot stand (i.e. minimum torque required by elbow motor to change from 0 to 90 degrees)?
Q-3)In a hexapod robot what is the minimum number of legs that are required to be grounded for both static stability as well as dynamic stability at slow speeds?
Q-4): A hexapod is fitted with ultrasonic sensor for navigation and is placed in a vacuum room for testing. After how long will the sensor receive an echo if it sends an ultrasonic beam towards a wall 3m away?
Q-5)Imagine a simple line follower track (as shown here) of black color on white surface. The robot comprises a chassis, two wheels, two motors, a motor driver, a battery and few discrete electronic components and just one IR Sensor Module. The robot (represented by red arrow) is placed as shown below. What should be the logic based on which the robot will follow the track and reach the end point? (Please give a high level logic which involves color of the surface and the robot direction only. We don’t expect you to go into the motor driver control, comparators etc.)
Q-6): Imagine a two-wheeled robot as shown in the figure here. The robot has two DC motors with rated speed of 60 rpm. The distance between the two wheels is around 20 cm. What should be the operating speeds of both the motors (outer and inner), such that the inner wheel covers a circle of 40 cm radius (as shown) in fastest possible time?
Q-7): Imagine a similar problem statement as (Question:6) for a hexapod robot having body width equal to 20 cm. If the speed of each motor is fixed at 60 rpm and cannot be varied, how will the robot achieve a circle of 40cm radius? (Note: just give the parameter that needs to be varied for each step. We don’t expect a gait sequence explanation)

None of these seem particularly difficult. Are you just in shock at the total amount asked? If so just take it one at a time and forget the rest. Do Q1 before moving onto Q2. What work have you done on these questions so far? I had a quick look at them and came up with the following ideas:

Q1 well, you can work this out. How many motors is that? How many control pins do you need for 1 motor? Multiply the two together for the answer; if that's 5 motors and 3 pins per motor, then that's 15 pins.

Q2 more number crunching. Work out the torque for 1 motor to do the work, then just divide it by 6, cos you've got 6 motors equally sharing the load. You could start by getting the units for torque and that will give you an idea where to plug the numbers in.

Q3 this one's not difficult. What is your initial guess?

Q4 partially depends on what a vacuum room is. If it's a room with a vacuum, never, because sound requires a medium to travel through. Assuming there is a medium, first you need the propagation time of ultrasound through that medium, then it's just a case of working out the total distance travelled by the wave then doing a division to get the time out (m divided by m/s = m/(m/s)=m*s/m=s).

Q5 have you thought this one through at all? Think about what should happen (a) if the sensor can see black, (b) if the sensor detects a black->white transition and (c) if the sensor detects a white->black transition. If the sensor detects white->black, how do you know which way to turn? Should the robot follow a line or an edge?

Q6 interesting, I would have thought this was dependent on the radius of the wheels. But this information is not given. Maybe it isn't, or perhaps the radius divides out. So assume a radius of x, or think up a number of test radii and work it out for each. But where are you stuck; this seems fairly simple to work out. The outer wheel needs to go faster than the inner wheel of course, so you can't have the inner wheel going at the maximum 60rpm.

Q7 seems fairly obvious, what do you think? Any guesses?

parthshah08 said:

Q-1)Consider a Hexapod robot having 6 shoulder joints and 6 elbow joints. Each joint uses 1 DC motor for actuation. How many digital control pins of a microcontroller are required to control the robot most effectively?
.... We don’t expect a gait sequence explanation)

Click to expand...

I believe you already posted this question somewhere on this forum. It is easier for everyone if you only post a question once, just so you know for future reference.
Best of luck!
Der Strom

Wasn't this assignment already due... why are you asking the same questions again?