Project

# Title Team Members TA Documents Sponsor
3 Robotic Manipulator with User Force-Feedback
Noah Franceschini
Sohan Patel
Jason Paximadas design_document1.pdf
final_paper1.pdf
photo1.jpg
photo2.jpg
presentation1.pptx
proposal1.pdf
Robotic Manipulator with User Force-Feedback

Team Members:
- Sohan Patel (sohankp2)
- Noah Franceschini (nef3)

**Problem**

A common need in Industry, and especially in today's increasingly virtual world is to interact with objects where it may not be possible from a logistic or health standpoint to do so. We have robotic manipulators and virtual simulations, but there is still a huge gap between real life and these current solutions. In a setting where an object is hazardous and may be fragile, it is paramount to be able to control how much pressure one is applying to the object, and be able to adjust it quickly and in a way that feels natural.

**Solution**

We would like to make two devices that work together to solve this issue. We want to create a manipulator that mirrors the user's movements and can accurately communicate the amount of force being exerted back to the user. The user would wear a glove that can track each finger's movement independently and apply the force experienced by the manipulator back to the user's hand. This would allow the wearer to easily discern the amount of force they are applying to an object without actually touching it themselves. This both solves the issue of being able to quickly and easily feel the force they are applying, as well as increasing user immersion, as wearing a glove is much more natural than using a different control mechanism. It would also allow a user to differentiate between objects quickly, for example the feeling of a foam ball vs a solid one.

**Subsystems**

**Glove**

This subsystem will be what the user actually wears, and will both track movements of each finger as well as apply the forces back to the wearer. It will need to support a wide range of resistance to motion, from light resistance as if one was squishing a foam ball, to being able to fully stop the fingers from moving

Components:

- Potentiometers or Flex sensors to determine the position of the user's fingers, will experiment with both
- Small motors to provide the required resistance to the fingers, or arrest movement entirely.

**Manipulator**

This subsystem will be what interacts with the object and relays resistance encountered by it to the glove. The manipulator itself will be 3D printed from an inexpensive plastic such as PLA.

Components:
- Small servos modified with low resistance shunt resistors to allow us to measure current, this allows us to know how much resistance each finger is encountering.

- 3D printed robot "hand" that has all the supporting structure needed to mount the electronics.

**Controller**

This is the brain of our project, it will be a microcontroller based device that can process the raw data coming from both the glove and manipulator, then facilitate the communication between the two.
Components:
- Microcontroller, ATmega328p or ATmega2560
- Stepper motor drivers
- Drivers for the user force-feedback, in the form of a motor and controller combination that can support dynamically adjusting the amount of tension.

**Criterion For Success**

- Track each finger and have the robot mirror those movements
- Measure the forces experienced by the manipulator
- Apply those forces to the user's hand
- Support resistance as well as stopping hand movement
- The user should be able to differentiate between a force caused by a solid object, vs one generated by a soft object compressing. The glove should not try and stop all movement in the latter case.
- Low latency operation, the manipulator should not have a delay more than .5 to 1 second.

Active Cell Balancing for Solar Vehicle Battery Pack

Tara D'Souza, John Han, Rohan Kamatar

Featured Project

# Problem

Illini Solar Car (ISC) utilizes lithium ion battery packs with 28 series modules of 15 parallel cells each. In order to ensure safe operation, each battery cell must remain in its safe voltage operating range (2.5 - 4.2 V). Currently, all modules charge and discharge simultaneously. If any single module reaches 4.2V while charging, or 2.5V while discharging, the car must stop charging or discharging, respectively. During normal use, it is natural for the modules to become unbalanced. As the pack grows more unbalanced, the capacity of the entire battery pack decreases as it can only charge and discharge to the range of the lowest capacity module. An actively balanced battery box would ensure that we utilize all possible charge during the race, up to 5% more charge based on previous calculations.

# Solution Overview

We will implement active balancing which will redistribute charge in order to fully utilize the capacity of every module. This system will be verified within a test battery box so that it can be incorporated into future solar vehicles.

Solution Components:

- Test Battery Box (Hardware): The test battery box provides an interface to test new battery management circuitry and active balancing.

- Battery Sensors (Hardware): The current battery sensors for ISC do not include hardware necessary for active balancing. The revised PCB will include the active balancing components proposed below while also including voltage and temperature sensing for each cell.

- Active Balancing Circuit (Hardware): The active balancing circuit includes a switching regulator IC, transformers, and the cell voltage monitors.

- BMS Test firmware (Software): The Battery Management System requires new firmware to control and test active balancing.

# Criterion for Success

- Charge can be redistributed from one module to another during discharge and charge, to be demonstrated by collected data of cell voltages over time.

- BMS can control balancing.

- The battery pack should always be kept within safe operating conditions.

- Test battery box provides a safe and usable platform for future tests.