An anti-sway" system in heavy lifting applications, particularly in crane operations, is designed to minimize or eliminate the swinging motion (also

Anti-swing System

An anti-sway" system in heavy lifting applications, particularly in crane operations, is designed to minimize or eliminate the swinging motion (also known as sway) of the load being lifted. This swinging can occur due to various factors such as wind, operator input, or external disturbances, and it can be hazardous to both the load and surrounding structures or personnel.

The anti-sway system typically employs sensors, control algorithms, and actuators to actively stabilize the load and reduce swinging. An anti-swing system generally includes the following parts:

Sensor: Sensors such as accelerometers, gyroscopes, load cells, and cameras are used to measure the position, velocity, and orientation of the load, as well as environmental conditions such as wind speed and direction.

Controller: Control algorithms analyze the sensor data in real-time to determine the current state of the load and predict its future motion. Based on this information, the control system generates corrective commands to counteract the sway and stabilize the load.

Actuator: The corrective commands are sent to actuators such as motor drives or hydraulic systems, which adjust the motion of the crane's hoist or trolley to minimize the sway of the load. These adjustments may involve varying the speed, acceleration, or position of the crane's movements.

The goal of the anti-sway system is to improve safety, increase efficiency, and reduce the risk of accidents during lifting operations. By actively stabilizing the load and minimizing sway, the system helps operators maintain precise control over heavy objects, ensuring accurate placement and preventing damage or injury due to swinging motions.

Swing Model

Assume we model a swing system with a simple pendulum length of l, as shown below.

If the pendulum starts its swing from some initial angle0, thenassuming that the angle is much less than 1 radian, we can estimate the angle at time t by t by solving the following PDE: 1,

d2dt2+gl=0,In this equation, g is the gravity and l is the length of the pendulum.

The solution to this equation is:

t= 0cosgl tThe approximate period of the motion is:

T0= 2lg

Real-Time Systems Knowledge Check

Based on your knowledge about real-time systems, what type of real-time system is an anti-swing system? Explain your answer.

Draw a block diagram that models a closed-loop anti-swing system. Clearly show the inputs and outputs of each block and explain the data type (Analog or digital) at the input and output of each block.

Which factors affect the total response time of your anti-swing system? How can one estimate each block's response time and your anti-swing system's total response time?

LTI System Modelling and Simulation

In an anti-swing system design by XYZ company, a camera is used to capture a picture of the pendulum and send it to a DSP. The DSP implements an image processing algorithm to estimate the swing angle (t).

Assume l is the last three least significant digits of your student ID is mm plus 100.

For example, if your student ID is 4001248264, consider l=264+100=364 mm and 0=0.1 Rad.

Plot t as a function of time for the swing system explained earlier (Pendulum). Your plot must show 2-3 periods of the signal. In your plot, indicate the signal's max, min, and period. Do not forget the axes titles and units!

Discuss weather the swing system is an LTI system and conditions which may change your answer.

Is it possible to design a real-time controller for a non LTI system?

Sampling and ADC conversion

How often should the camera take a snapshot of the pendulum? Suggest an appropriate sampling rate for your system. Explain the criteria you used to determine the sampling rate.

Considering an 8-bit digital value for variable in your DSP, plot [n] using a sample and hold system with the sampling rate you suggested earlier.

Explain the potential effects of changing the sampling rate to a faster or slower rate. How does the sampling rate affect the overall performance of your anti-swing system?

Drift Problem

Explain the source of drift in the anti-swing system and how it may affect its performance.

Explain a situation where the software drift can endanger the life of people working around a crane.

Suggest a solution to mitigate the risk explained in the previous part.

Processor Architecture.

Assume the image processing algorithm used in your anti-swing system has 6780 lines of assembly code. This algorithm estimates the swing angle given the image of the pendulum. The code runs on a CISC architecture microcontroller with an average processing speed of 13 microseconds per instruction.

Calculate the software delay in this application.

Explain whether this software delay is acceptable in your ant-swing application.

The software team wants to try a convolutional neural network and implement a more advanced image processing algorithm. Determine the maximum number of assembly lines they may run on this microcontroller safely without missing any image samples.