IV. Mechanical analysis for the manipulator arm
In this section, the static analysis, forward kinematics and inverse kinematics for the manipulator arm will be discussed.
A. Static Analysis
The static analysis is very significant in manipulator’s design to roughly approximate the required torques from each motor. In our design, it is important to check the stability of the quadcopter that the manipulator is integrated on it in terms of manipulator arm center of mass shifting as function of joint angles; as mentioned before the excessive shifting of the quadcopter center of mass usually lead to loss the stability of it.
In figure (4), the schematic diagram of the manipulator arm is shown, where t1 is the yaw angle of the manipulator arm, …show more content…
Dynamic Analysis of The manipulator arm
The significance of making dynamic analysis for the manipulator is to determine accurately the torques that are required to carry a specific amount of load on the end effector at a particular position with a predetermined acceleration and velocity. The dynamic analysis is mainly used to determine the maximum torque needed during the mission; in order to select the DC-servomotors needed for each joint.
Usually in case of complex manipulator it is suitable to use Lagrangian approach to get to do the dynamic analysis instead of Newton’s approach; which is done by calculating the position of the center of mass for each link including the end effectors as function of joint angles in the universal frame then take the derivative of each position as function of time then calculate the angular velocity of each body in the universal frame then calculate the rotation matrix from each body frame to the universal frame then we calculate the inertia of each body in its frame then convert it to the universal frame using the rotation matrix then calculate the kinetic and potential energy for each body as follows: …show more content…
F. Power Calculation for motors selection
Selection of motors needs to make a dynamic analysis to the manipulator arm to calculate the required torques then multiply it by the angular velocities to get the power, then select the motor that can give the same or little bit higher power than the required (by multiplying by factor of safety) ; if the motor have a small torque and big angular velocity gearbox is used to increase torque and decrease angular velocity (the power will not changed due to conservation of power as long as there is no friction).
〖Power〗_i=T_i*w_i
V. Design Specifications
The manipulator arm design was based on Kitty Hawk quadrotor that can carry up to 4.3 kg payload and has a (Width: 42” Length: 40” Height: 10”). The selected material for our design is a 3D-printable Pla fiber because it has a very small specific weight and a good strength for our mission.
Dimensions Mass(gram)
L1 150 (mm) 18.75
L2 150 (mm) 18.75
L3 150 (mm) 18.75
L4 145 (mm) 18.125
L5 50 (mm) 6.25
L6 50 (mm) 6.25
Count. Bal. mass --------------- 0.4
In this section, the static analysis, forward kinematics and inverse kinematics for the manipulator arm will be discussed.
A. Static Analysis
The static analysis is very significant in manipulator’s design to roughly approximate the required torques from each motor. In our design, it is important to check the stability of the quadcopter that the manipulator is integrated on it in terms of manipulator arm center of mass shifting as function of joint angles; as mentioned before the excessive shifting of the quadcopter center of mass usually lead to loss the stability of it.
In figure (4), the schematic diagram of the manipulator arm is shown, where t1 is the yaw angle of the manipulator arm, …show more content…
Dynamic Analysis of The manipulator arm
The significance of making dynamic analysis for the manipulator is to determine accurately the torques that are required to carry a specific amount of load on the end effector at a particular position with a predetermined acceleration and velocity. The dynamic analysis is mainly used to determine the maximum torque needed during the mission; in order to select the DC-servomotors needed for each joint.
Usually in case of complex manipulator it is suitable to use Lagrangian approach to get to do the dynamic analysis instead of Newton’s approach; which is done by calculating the position of the center of mass for each link including the end effectors as function of joint angles in the universal frame then take the derivative of each position as function of time then calculate the angular velocity of each body in the universal frame then calculate the rotation matrix from each body frame to the universal frame then we calculate the inertia of each body in its frame then convert it to the universal frame using the rotation matrix then calculate the kinetic and potential energy for each body as follows: …show more content…
F. Power Calculation for motors selection
Selection of motors needs to make a dynamic analysis to the manipulator arm to calculate the required torques then multiply it by the angular velocities to get the power, then select the motor that can give the same or little bit higher power than the required (by multiplying by factor of safety) ; if the motor have a small torque and big angular velocity gearbox is used to increase torque and decrease angular velocity (the power will not changed due to conservation of power as long as there is no friction).
〖Power〗_i=T_i*w_i
V. Design Specifications
The manipulator arm design was based on Kitty Hawk quadrotor that can carry up to 4.3 kg payload and has a (Width: 42” Length: 40” Height: 10”). The selected material for our design is a 3D-printable Pla fiber because it has a very small specific weight and a good strength for our mission.
Dimensions Mass(gram)
L1 150 (mm) 18.75
L2 150 (mm) 18.75
L3 150 (mm) 18.75
L4 145 (mm) 18.125
L5 50 (mm) 6.25
L6 50 (mm) 6.25
Count. Bal. mass --------------- 0.4