I need to update the droid’s rear linear actuator. The old one was giving me a play of about 1-2 cm which is really bad when it swings the new weight of the arms. Each B1 robotic arm weighs 8kg which is adding a total of about 50lbs to the top of the droid including the head camera. For this reason I decided to update the LACT. Not to mention the bottom bolt which was 1/4 inch was snapping off with all the weight that is being required. it’s time to upgrade! I never remember to log these things so here is my attempt to keep you posted.

Here is a picture of  the new LACT with the 18AWG cable cut to size.

Here is a pic of the old LACT. You can see the smaller size of the mounting hardware if you compare to the other pics.

Under that blob of black shrink wrap protection is the motor controller. You will find it is the Pololu Jrk Motor Controller series which talks to the microcontroller with the green and yellow wires. You can also use USB serial and I highly recommend this controller for powerful professional applications. In the next frames we will cut away the protection and install the new LACT. LACT has + and - and you can reverse them in order to make the LACT go up or down.

Here you can see 4 ports for wires. The outside 2 are for the power cables and cannot be reversed or you will blow the motor controller. The center 2 are for the LACT. We replace these with red on the left so that the code we already have works the same with no changes.

Use Electrical tape as we never want something to short circuiting there. its a garbled mess of wires and I apologize. One day I will be able to make a circuit board customized for this so that the wires are organized and manageable.

The bolt that mounts this thing is 1/4 inch and snaps off after a bit of usage. Very bad on my part to have made such a weak connection. It needs to be a 1/2 inch bolt holding this plate of metal that hold the LACT mount. If you look close you will also see 1/4 inch steel plate to reinforce the back. Honestly this whole thing needs to be steel, as I have reached the limitations of maple plywood. On the bright side this tells me exactly what to reinforce on the steel/aluminum droid design.

Notice how badly it was bending this steel corner brace

Here you can see I made a new corner brace into a u shaped bracket that will hold the new LACT medium duty mount. I ordered it just now so we will have to put this aside until it arrives. Patience.

Here you can see the upper stage being unbolted from the LACT.

Close up shop until the new parts arrive. I thought I could get away with the old aluminum light duty actuator holder or modify the original but you can’t. The new aluminum part costs 55$ and its 2inches wide not 1.5 inches so its more metal to hold the weight. its for the best and I should have noticed the size difference between them. It even holds a 3/8 bolt across instead of 5/16 so I need to upgrade the bolt at the top joint as well.