I have been playing around with the idea of making an aftermarket ABS system older bikes like the BUSA. I’m going to tell you all of these ideas because under no circumstances am I going to market something like this (liability, who knows if any of this will actually work). It seems that the ABS systems on most bikes are overly complex because they have pumps and separate the rider from control feel through the brakes. I was thinking to just use actuators to “correct†bad inputs from the rider.
Basically there would be 2 master cylinders (MC) at each wheel. The primary MC is the one you already have on the bike and that your control lever operates. The second MC would be linked opposite of the primary. Rather than being normally “open†and then closing to increase pressure in the hydraulic line like a typical MC, the second MC would normally be “closed†and would be “opened†to reduce hydraulic line pressure.
The secondary MC would be controlled by an electronic actuator, which would be controlled by a microprocessor. When you apply too much braking force to the lever and primary MC, the secondary MC would reduce the pressure, “correcting†your input so the wheel does not lock up. The advantage of this setup is that it could be very light, maybe a couple pounds for each wheel. Second, you would have much of the feel of the normal braking system as you are still linked to the caliper through the hydraulic line (some systems, like the Honda system you are “braking by wireâ€).
Now for the sensors. The microprocessor is pretty cheap – about $100. We will need a very good industrial linear actuator - $200 or so. I propose to create a GPS speedometer for the bike that would be a part of this system. This is also pretty cheap, probably $200 or so. Using the GPS speed indicator gives an absolute speed, independent of wheel slip, gearing changes, etc. It also gets us the ability to include lean angle in our control algorithm. We will use a standard induction type wheel position indicator to monitor wheel speed at both ends of the bike.
The microcontroller would compare wheel speed at each wheel to the bikes GPS speed. If a wheel is spinning a certain amount too slow relative to the GPS speed, the secondary MC is opened up until the wheel speeds are again consistent. It would be easy to allow a certain amount of slip, especially in the rear wheels, and you could allow some configuration by the rider here. The system could also be turned off completely, at which case the brakes would be essentially stock in their function and feel.
If we really wanted to get slick, we could add lean information. For example, if the bike is upright a small amount of wheel slip could be allowed. If the bike is leaned over, the system would act aggressively on any slip. The lean angle would also allow the system to adjust how quickly or aggressively it reacts to wheel slip. For example if you are riding in a straight line and grab a hand full of brake. The system would sense that the bike is straight up and allow some slipping to get maximum braking performance.
Fault tolerance is easy too. If a sensor is not sending or sending erroneous information (negative speed or excessive speed) the system would shut off and close the secondary MC, so the brakes would work as stock.
All of this might sound like techno-mumbo-jumbo but i'm convienced it’s possible with off the shelf stuff. If anyone is interested in playing around with it PM me. I don’t have the hydraulic experience I need to get the secondary MC part done but I think I can handle the electronics and programming.
Basically there would be 2 master cylinders (MC) at each wheel. The primary MC is the one you already have on the bike and that your control lever operates. The second MC would be linked opposite of the primary. Rather than being normally “open†and then closing to increase pressure in the hydraulic line like a typical MC, the second MC would normally be “closed†and would be “opened†to reduce hydraulic line pressure.
The secondary MC would be controlled by an electronic actuator, which would be controlled by a microprocessor. When you apply too much braking force to the lever and primary MC, the secondary MC would reduce the pressure, “correcting†your input so the wheel does not lock up. The advantage of this setup is that it could be very light, maybe a couple pounds for each wheel. Second, you would have much of the feel of the normal braking system as you are still linked to the caliper through the hydraulic line (some systems, like the Honda system you are “braking by wireâ€).
Now for the sensors. The microprocessor is pretty cheap – about $100. We will need a very good industrial linear actuator - $200 or so. I propose to create a GPS speedometer for the bike that would be a part of this system. This is also pretty cheap, probably $200 or so. Using the GPS speed indicator gives an absolute speed, independent of wheel slip, gearing changes, etc. It also gets us the ability to include lean angle in our control algorithm. We will use a standard induction type wheel position indicator to monitor wheel speed at both ends of the bike.
The microcontroller would compare wheel speed at each wheel to the bikes GPS speed. If a wheel is spinning a certain amount too slow relative to the GPS speed, the secondary MC is opened up until the wheel speeds are again consistent. It would be easy to allow a certain amount of slip, especially in the rear wheels, and you could allow some configuration by the rider here. The system could also be turned off completely, at which case the brakes would be essentially stock in their function and feel.
If we really wanted to get slick, we could add lean information. For example, if the bike is upright a small amount of wheel slip could be allowed. If the bike is leaned over, the system would act aggressively on any slip. The lean angle would also allow the system to adjust how quickly or aggressively it reacts to wheel slip. For example if you are riding in a straight line and grab a hand full of brake. The system would sense that the bike is straight up and allow some slipping to get maximum braking performance.
Fault tolerance is easy too. If a sensor is not sending or sending erroneous information (negative speed or excessive speed) the system would shut off and close the secondary MC, so the brakes would work as stock.
All of this might sound like techno-mumbo-jumbo but i'm convienced it’s possible with off the shelf stuff. If anyone is interested in playing around with it PM me. I don’t have the hydraulic experience I need to get the secondary MC part done but I think I can handle the electronics and programming.