I have been working on a robotics project using the Arduino Uno and a prototype shield, which up to this point has been working just fine. Before today I had a servo motor attached to the front of the robot with an attached blade that simply swung up and down, and did not cause any problems with the function of the robot even when meeting physical resistance(I use an IR remote to drive the wheels and activate the servo's up and down movement). I just installed a gripper claw in place of the swinging blade, which works properly, but when the gripper claw grabs an object (in which case the claw does not close completely and makes a whirring noise as it tries to close completely), it causes the motors in the wheels to begin moving forward in intermittent, jerking motions, as if the drive function had been activated. Also, the LED I have wired to an ultrasonic range finder comes on as if it has detected an obstacle, and the indicator light on the arduino board turns yellow. Is it possible some charge is sent back from the motor and making these other sensors activate? The robot has never done this before, and the wheel motors should not activate unless I send specific values with the IR remote or a button is pressed on the prototype board. The specific servo motor I'm using is an SG90 tower pro micro servo.
Thank you for any advice you can give.
The standard forum answer whenever servos misbehave is "how is this whole thing powered?"
Hopefully the servo has its own power and is not powered from the Arduino's 5V output, and you have all the grounds commoned to make good return paths.
You circuit description would be better if there was a schematic for us to look at.
but when the gripper claw grabs an object (in which case the claw does not close completely and makes a whirring noise as it tries to close completely),
That is the servo straining against the gripper and possibly slipping/stripping the internal gears. If the servo is powered from the arduino, this will cause a low voltage condition on the arduino (similar to shorting out the power supply).
I'm glad to learn that servos should be powered externally before i did any damage to my other electronics, the example guide that came with my board had the servo being connected directly to the 5V pin. Attaching the servo's power wire to a separate positive power source seems to have fixed it, thank you. (I did break the internal gears of my servo while experimenting with attachments, but seeing as it's a $2 motor I think it's worth the learning experience) 
An inexpensive learning moment. Don't throw the servo away as it probably can be used to drive a large H-bridge like below in the event you decide to go big later.